diff --git a/CHANGELOG.md b/CHANGELOG.md
index c25166fb..e16510af 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,8 +2,15 @@
 
 ## [Unreleased]
 
+### Added
+* `select` query parameter support for list and find operations on contacts, messages, events, threads, folders, calendars, and attachments
+* `FindFolderQueryParams`, `FindThreadQueryParams`, and `FindCalendarQueryParams` classes for find operations with select support
+* Comprehensive test coverage for select parameter functionality across all supported endpoints
+* Extensive examples demonstrating proper usage of select parameter with all endpoints
+
 ### Changed
 * `SendMessageRequest.sendAt` field changed from `Int?` to `Long?` to support Unix timestamps beyond 2038. Maintains backward compatibility through method overloading - existing `Int` parameters are automatically converted to `Long`. **Note:** Kotlin users passing integer literals may need to specify type explicitly (e.g., `1620000000L` or `1620000000 as Int`).
+* Model properties (`grantId`, `id`, and other required fields) are now optional in `Message`, `Contact`, `Event`, `Thread`, `Folder`, and `Calendar` to support select query parameter functionality
 
 ## [2.13.1]
 
diff --git a/examples/src/main/kotlin/com/nylas/examples/KotlinFoldersExample.kt b/examples/src/main/kotlin/com/nylas/examples/KotlinFoldersExample.kt
index 631bdc49..a4238bcb 100644
--- a/examples/src/main/kotlin/com/nylas/examples/KotlinFoldersExample.kt
+++ b/examples/src/main/kotlin/com/nylas/examples/KotlinFoldersExample.kt
@@ -86,12 +86,14 @@ fun main() {
         val comprehensiveFolders = nylasClient.folders().list(grantId, comprehensiveParams)
         println("Found ${comprehensiveFolders.data.size} folders with comprehensive options:")
         comprehensiveFolders.data.forEach { folder ->
-            println("  - ${folder.name}")
-            println("    ID: ${folder.id}")
+            println("  - ${folder.name ?: "N/A"}")
+            println("    ID: ${folder.id ?: "N/A"}")
             println("    Unread Count: ${folder.unreadCount ?: 0}")
             if (folder.parentId != null) {
                 println("    Parent ID: ${folder.parentId}")
             }
+            // Note: When using select parameter, only selected fields are returned
+            // grantId and other fields may be null if not included in select
             println()
         }
 
diff --git a/examples/src/main/kotlin/com/nylas/examples/SelectParameterExample.kt b/examples/src/main/kotlin/com/nylas/examples/SelectParameterExample.kt
new file mode 100644
index 00000000..92ae7478
--- /dev/null
+++ b/examples/src/main/kotlin/com/nylas/examples/SelectParameterExample.kt
@@ -0,0 +1,361 @@
+package com.nylas.examples
+
+import com.nylas.NylasClient
+import com.nylas.models.*
+
+/**
+ * Example demonstrating how to use the select parameter with various Nylas endpoints.
+ * 
+ * The select parameter allows you to specify which fields you want returned in the response,
+ * which can help optimize response size and reduce latency by limiting queries to only 
+ * the information that you need.
+ * 
+ * When using select, fields not included in the select parameter will be null in the response objects.
+ */
+class SelectParameterExample {
+
+    private val client = NylasClient(
+        apiKey = "YOUR_API_KEY"
+    )
+
+    /**
+     * Example: List folders with select parameter
+     * Only returns id and name fields, grant_id will be null
+     */
+    fun listFoldersWithSelect() {
+        try {
+            val queryParams = ListFoldersQueryParams.Builder()
+                .limit(10)
+                .select("id,name")  // Only return id and name
+                .build()
+
+            val response = client.folders().list("grant-id", queryParams)
+            
+            response.data.forEach { folder ->
+                println("Folder ID: ${folder.id}")
+                println("Folder Name: ${folder.name}")
+                println("Grant ID: ${folder.grantId}") // This will be null because not in select
+                println("---")
+            }
+        } catch (e: Exception) {
+            println("Error listing folders: ${e.message}")
+        }
+    }
+
+    /**
+     * Example: Find folder with select parameter
+     * Only returns id, name, and grant_id fields
+     */
+    fun findFolderWithSelect() {
+        try {
+            val queryParams = FindFolderQueryParams.Builder()
+                .select("id,name,grant_id")
+                .build()
+
+            val response = client.folders().find("grant-id", "folder-id", queryParams)
+            val folder = response.data
+            
+            println("Folder ID: ${folder.id}")
+            println("Folder Name: ${folder.name}")
+            println("Grant ID: ${folder.grantId}")
+            println("Parent ID: ${folder.parentId}") // This will be null because not in select
+        } catch (e: Exception) {
+            println("Error finding folder: ${e.message}")
+        }
+    }
+
+    /**
+     * Example: List contacts with select parameter
+     * Only returns id, display_name, and emails
+     */
+    fun listContactsWithSelect() {
+        try {
+            val queryParams = ListContactsQueryParams.Builder()
+                .limit(5)
+                .select("id,display_name,emails")
+                .build()
+
+            val response = client.contacts().list("grant-id", queryParams)
+            
+            response.data.forEach { contact ->
+                println("Contact ID: ${contact.id}")
+                println("Display Name: ${contact.displayName}")
+                println("Emails: ${contact.emails?.map { it.email }}")
+                println("Grant ID: ${contact.grantId}") // This will be null because not in select
+                println("---")
+            }
+        } catch (e: Exception) {
+            println("Error listing contacts: ${e.message}")
+        }
+    }
+
+    /**
+     * Example: Find contact with select parameter
+     */
+    fun findContactWithSelect() {
+        try {
+            val queryParams = FindContactQueryParams.Builder()
+                .select("id,display_name,grant_id")
+                .profilePicture(true)
+                .build()
+
+            val response = client.contacts().find("grant-id", "contact-id", queryParams)
+            val contact = response.data
+            
+            println("Contact ID: ${contact.id}")
+            println("Display Name: ${contact.displayName}")
+            println("Grant ID: ${contact.grantId}")
+            println("Phone Numbers: ${contact.phoneNumbers}") // This will be null because not in select
+        } catch (e: Exception) {
+            println("Error finding contact: ${e.message}")
+        }
+    }
+
+    /**
+     * Example: List messages with select parameter
+     * Only returns id, subject, and from fields
+     */
+    fun listMessagesWithSelect() {
+        try {
+            val queryParams = ListMessagesQueryParams.Builder()
+                .limit(10)
+                .select("id,subject,from")
+                .build()
+
+            val response = client.messages().list("grant-id", queryParams)
+            
+            response.data.forEach { message ->
+                println("Message ID: ${message.id}")
+                println("Subject: ${message.subject}")
+                println("From: ${message.from?.map { "${it.name} <${it.email}>" }}")
+                println("Grant ID: ${message.grantId}") // This will be null because not in select
+                println("---")
+            }
+        } catch (e: Exception) {
+            println("Error listing messages: ${e.message}")
+        }
+    }
+
+    /**
+     * Example: Find message with select parameter
+     */
+    fun findMessageWithSelect() {
+        try {
+            val queryParams = FindMessageQueryParams.Builder()
+                .select("id,subject,body,grant_id")
+                .fields(MessageFields.STANDARD)
+                .build()
+
+            val response = client.messages().find("grant-id", "message-id", queryParams)
+            val message = response.data
+            
+            println("Message ID: ${message.id}")
+            println("Subject: ${message.subject}")
+            println("Body: ${message.body}")
+            println("Grant ID: ${message.grantId}")
+            println("Attachments: ${message.attachments}") // This will be null because not in select
+        } catch (e: Exception) {
+            println("Error finding message: ${e.message}")
+        }
+    }
+
+    /**
+     * Example: List threads with select parameter
+     */
+    fun listThreadsWithSelect() {
+        try {
+            val queryParams = ListThreadsQueryParams.Builder()
+                .limit(10)
+                .select("id,subject,latest_draft_or_message")
+                .build()
+
+            val response = client.threads().list("grant-id", queryParams)
+            
+            response.data.forEach { thread ->
+                println("Thread ID: ${thread.id}")
+                println("Subject: ${thread.subject}")
+                println("Latest Message: ${thread.latestDraftOrMessage}")
+                println("Grant ID: ${thread.grantId}") // This will be null because not in select
+                println("---")
+            }
+        } catch (e: Exception) {
+            println("Error listing threads: ${e.message}")
+        }
+    }
+
+    /**
+     * Example: Find thread with select parameter
+     */
+    fun findThreadWithSelect() {
+        try {
+            val queryParams = FindThreadQueryParams.Builder()
+                .select("id,subject,grant_id")
+                .build()
+
+            val response = client.threads().find("grant-id", "thread-id", queryParams)
+            val thread = response.data
+            
+            println("Thread ID: ${thread.id}")
+            println("Subject: ${thread.subject}")
+            println("Grant ID: ${thread.grantId}")
+            println("Message IDs: ${thread.messageIds}") // This will be null because not in select
+        } catch (e: Exception) {
+            println("Error finding thread: ${e.message}")
+        }
+    }
+
+    /**
+     * Example: List events with select parameter
+     */
+    fun listEventsWithSelect() {
+        try {
+            val queryParams = ListEventQueryParams.Builder("primary")
+                .limit(10)
+                .select("id,title,when")
+                .build()
+
+            val response = client.events().list("grant-id", queryParams)
+            
+            response.data.forEach { event ->
+                println("Event ID: ${event.id}")
+                println("Title: ${event.title}")
+                println("When: ${event.`when`}")
+                println("Grant ID: ${event.grantId}") // This will be null because not in select
+                println("---")
+            }
+        } catch (e: Exception) {
+            println("Error listing events: ${e.message}")
+        }
+    }
+
+    /**
+     * Example: Find event with select parameter
+     */
+    fun findEventWithSelect() {
+        try {
+            val queryParams = FindEventQueryParams.Builder("primary")
+                .select("id,title,description,grant_id")
+                .build()
+
+            val response = client.events().find("grant-id", "event-id", queryParams)
+            val event = response.data
+            
+            println("Event ID: ${event.id}")
+            println("Title: ${event.title}")
+            println("Description: ${event.description}")
+            println("Grant ID: ${event.grantId}")
+            println("Participants: ${event.participants}") // This will be null because not in select
+        } catch (e: Exception) {
+            println("Error finding event: ${e.message}")
+        }
+    }
+
+    /**
+     * Example: List calendars with select parameter
+     */
+    fun listCalendarsWithSelect() {
+        try {
+            val queryParams = ListCalendersQueryParams.Builder()
+                .limit(10)
+                .select("id,name,description")
+                .build()
+
+            val response = client.calendars().list("grant-id", queryParams)
+            
+            response.data.forEach { calendar ->
+                println("Calendar ID: ${calendar.id}")
+                println("Name: ${calendar.name}")
+                println("Description: ${calendar.description}")
+                println("Grant ID: ${calendar.grantId}") // This will be null because not in select
+                println("---")
+            }
+        } catch (e: Exception) {
+            println("Error listing calendars: ${e.message}")
+        }
+    }
+
+    /**
+     * Example: Find calendar with select parameter
+     */
+    fun findCalendarWithSelect() {
+        try {
+            val queryParams = FindCalendarQueryParams.Builder()
+                .select("id,name,grant_id")
+                .build()
+
+            val response = client.calendars().find("grant-id", "calendar-id", queryParams)
+            val calendar = response.data
+            
+            println("Calendar ID: ${calendar.id}")
+            println("Name: ${calendar.name}")
+            println("Grant ID: ${calendar.grantId}")
+            println("Timezone: ${calendar.timezone}") // This will be null because not in select
+        } catch (e: Exception) {
+            println("Error finding calendar: ${e.message}")
+        }
+    }
+
+    /**
+     * Example: Find attachment with select parameter
+     */
+    fun findAttachmentWithSelect() {
+        try {
+            val queryParams = FindAttachmentQueryParams.Builder("message-id")
+                .select("id,filename,content_type")
+                .build()
+
+            val response = client.attachments().find("grant-id", "attachment-id", queryParams)
+            val attachment = response.data
+            
+            println("Attachment ID: ${attachment.id}")
+            println("Filename: ${attachment.filename}")
+            println("Content Type: ${attachment.contentType}")
+            println("Grant ID: ${attachment.grantId}") // This will be null because not in select
+        } catch (e: Exception) {
+            println("Error finding attachment: ${e.message}")
+        }
+    }
+
+    /**
+     * Example: Download attachment with select parameter
+     * Note: The download itself returns the binary data, but you can still use select 
+     * to limit the metadata returned in other operations
+     */
+    fun downloadAttachmentWithSelect() {
+        try {
+            val queryParams = FindAttachmentQueryParams.Builder("message-id")
+                .select("id,filename,content_type,size")
+                .build()
+
+            // Download the attachment data
+            val responseBody = client.attachments().download("grant-id", "attachment-id", queryParams)
+            val data = responseBody.bytes()
+            responseBody.close()
+            
+            println("Downloaded ${data.size} bytes")
+        } catch (e: Exception) {
+            println("Error downloading attachment: ${e.message}")
+        }
+    }
+}
+
+fun main() {
+    val example = SelectParameterExample()
+    
+    println("=== Select Parameter Examples ===")
+    println()
+    
+    println("1. List folders with select:")
+    example.listFoldersWithSelect()
+    println()
+    
+    println("2. Find folder with select:")
+    example.findFolderWithSelect()
+    println()
+    
+    println("3. List contacts with select:")
+    example.listContactsWithSelect()
+    println()
+    
+    // Add more examples as needed...
+}
diff --git a/src/main/kotlin/com/nylas/models/Calendar.kt b/src/main/kotlin/com/nylas/models/Calendar.kt
index a72784b1..ab14e45a 100644
--- a/src/main/kotlin/com/nylas/models/Calendar.kt
+++ b/src/main/kotlin/com/nylas/models/Calendar.kt
@@ -10,17 +10,17 @@ data class Calendar(
    * Globally unique object identifier.
    */
   @Json(name = "id")
-  val id: String = "",
+  val id: String? = null,
   /**
    * Grant ID of the Nylas account.
    */
   @Json(name = "grant_id")
-  val grantId: String = "",
+  val grantId: String? = null,
   /**
    * Name of the Calendar.
    */
   @Json(name = "name")
-  val name: String = "",
+  val name: String? = null,
   /**
    * The type of object.
    */
@@ -31,22 +31,22 @@ data class Calendar(
    * @see <a href="https://en.wikipedia.org/wiki/List_of_tz_database_time_zones">List of tz database time zones</a>
    */
   @Json(name = "timezone")
-  val timezone: String = "",
+  val timezone: String? = null,
   /**
    * If the event participants are able to edit the event.
    */
   @Json(name = "read_only")
-  val readOnly: Boolean = false,
+  val readOnly: Boolean? = null,
   /**
    * If the calendar is owned by the user account.
    */
   @Json(name = "is_owned_by_user")
-  val isOwnedByUser: Boolean = false,
+  val isOwnedByUser: Boolean? = null,
   /**
    * If the calendar is the primary calendar.
    */
   @Json(name = "is_primary")
-  val isPrimary: Boolean = false,
+  val isPrimary: Boolean? = null,
   /**
    * Description of the calendar.
    */
diff --git a/src/main/kotlin/com/nylas/models/Contact.kt b/src/main/kotlin/com/nylas/models/Contact.kt
index 5a80c4ab..f0dc9d1c 100644
--- a/src/main/kotlin/com/nylas/models/Contact.kt
+++ b/src/main/kotlin/com/nylas/models/Contact.kt
@@ -7,9 +7,9 @@ import com.squareup.moshi.Json
  */
 data class Contact(
   @Json(name = "id")
-  val id: String = "",
+  val id: String? = null,
   @Json(name = "grant_id")
-  val grantId: String = "",
+  val grantId: String? = null,
   @Json(name = "object")
   private val obj: String = "contact",
   @Json(name = "birthday")
@@ -17,7 +17,7 @@ data class Contact(
   @Json(name = "company_name")
   val companyName: String? = null,
   @Json(name = "display_name")
-  val displayName: String = "",
+  val displayName: String? = null,
   @Json(name = "emails")
   val emails: List<ContactEmail>? = null,
   @Json(name = "im_addresses")
diff --git a/src/main/kotlin/com/nylas/models/Event.kt b/src/main/kotlin/com/nylas/models/Event.kt
index bd476a54..8f486a0d 100644
--- a/src/main/kotlin/com/nylas/models/Event.kt
+++ b/src/main/kotlin/com/nylas/models/Event.kt
@@ -10,12 +10,12 @@ data class Event(
    * Globally unique object identifier.
    */
   @Json(name = "id")
-  val id: String = "",
+  val id: String? = null,
   /**
    * Grant ID of the Nylas account.
    */
   @Json(name = "grant_id")
-  val grantId: String = "",
+  val grantId: String? = null,
   /**
    * Representation of time and duration for events. When object can be in one of four formats (sub-objects):
    * - [When.Date]
@@ -24,22 +24,22 @@ data class Event(
    * - [When.Timespan]
    */
   @Json(name = "when")
-  private val whenObj: When = When.Time(0),
+  private val whenObj: When? = null,
   /**
    * This value determines whether to show this event's time block as available on shared or public calendars.
    */
   @Json(name = "busy")
-  val busy: Boolean = false,
+  val busy: Boolean? = null,
   /**
    * Calendar ID of the event.
    */
   @Json(name = "calendar_id")
-  val calendarId: String = "",
+  val calendarId: String? = null,
   /**
    * Whether participants of the event should be hidden.
    */
   @Json(name = "hide_participants")
-  val hideParticipants: Boolean = false,
+  val hideParticipants: Boolean? = null,
   /**
    * The type of object.
    */
@@ -49,17 +49,17 @@ data class Event(
    * List of participants invited to the event. Participants may also be rooms or resources.
    */
   @Json(name = "participants")
-  val participants: List<Participant> = emptyList(),
+  val participants: List<Participant>? = null,
   /**
    * If the event participants are able to edit the event.
    */
   @Json(name = "read_only")
-  val readOnly: Boolean = false,
+  val readOnly: Boolean? = null,
   /**
    * Visibility of the event, if the event is private or public.
    */
   @Json(name = "visibility")
-  val visibility: EventVisibility = EventVisibility.DEFAULT,
+  val visibility: EventVisibility? = null,
   /**
    * Representation of conferencing details for events. Conferencing object can be in one of two formats (sub-objects):
    * - [Conferencing.Autocreate]
@@ -164,7 +164,7 @@ data class Event(
 
   /**
    * Get the representation of time and duration for events.
-   * @return The representation of time and duration for events.
+   * @return The representation of time and duration for events, or null if not set.
    */
-  fun getWhen(): When = whenObj
+  fun getWhen(): When? = whenObj
 }
diff --git a/src/main/kotlin/com/nylas/models/FindAttachmentQueryParams.kt b/src/main/kotlin/com/nylas/models/FindAttachmentQueryParams.kt
index e8d8286f..db882795 100644
--- a/src/main/kotlin/com/nylas/models/FindAttachmentQueryParams.kt
+++ b/src/main/kotlin/com/nylas/models/FindAttachmentQueryParams.kt
@@ -11,6 +11,13 @@ data class FindAttachmentQueryParams(
    */
   @Json(name = "message_id")
   val messageId: String,
+  /**
+   * Specify fields that you want Nylas to return, as a comma-separated list (for example, select=id,updated_at).
+   * This allows you to receive only the portion of object data that you're interested in.
+   * You can use select to optimize response size and reduce latency by limiting queries to only the information that you need
+   */
+  @Json(name = "select")
+  var select: String? = null,
 ) : IQueryParams {
   /**
    * Builder for [FindAttachmentQueryParams].
@@ -19,12 +26,22 @@ data class FindAttachmentQueryParams(
   data class Builder(
     private val messageId: String,
   ) {
+    private var select: String? = null
+
+    /**
+     * Sets the fields to select.
+     * @param select The fields to select.
+     * @return The builder.
+     */
+    fun select(select: String?) = apply { this.select = select }
+
     /**
      * Builds a new [FindAttachmentQueryParams] instance.
      * @return [FindAttachmentQueryParams]
      */
     fun build() = FindAttachmentQueryParams(
       messageId,
+      select,
     )
   }
 }
diff --git a/src/main/kotlin/com/nylas/models/FindCalendarQueryParams.kt b/src/main/kotlin/com/nylas/models/FindCalendarQueryParams.kt
new file mode 100644
index 00000000..c7302c62
--- /dev/null
+++ b/src/main/kotlin/com/nylas/models/FindCalendarQueryParams.kt
@@ -0,0 +1,38 @@
+package com.nylas.models
+
+import com.squareup.moshi.Json
+
+/**
+ * Class representing the query parameters for finding a calendar.
+ */
+data class FindCalendarQueryParams(
+  /**
+   * Specify fields that you want Nylas to return, as a comma-separated list (for example, select=id,updated_at).
+   * This allows you to receive only the portion of object data that you're interested in.
+   * You can use select to optimize response size and reduce latency by limiting queries to only the information that you need
+   */
+  @Json(name = "select")
+  var select: String? = null,
+) : IQueryParams {
+  /**
+   * Builder for [FindCalendarQueryParams].
+   */
+  class Builder {
+    private var select: String? = null
+
+    /**
+     * Sets the fields to select.
+     * @param select The fields to select.
+     * @return The builder.
+     */
+    fun select(select: String?) = apply { this.select = select }
+
+    /**
+     * Builds the [FindCalendarQueryParams] object.
+     * @return The [FindCalendarQueryParams] object.
+     */
+    fun build() = FindCalendarQueryParams(
+      select = select,
+    )
+  }
+}
diff --git a/src/main/kotlin/com/nylas/models/FindContactQueryParams.kt b/src/main/kotlin/com/nylas/models/FindContactQueryParams.kt
index 9e5970fd..226b7db8 100644
--- a/src/main/kotlin/com/nylas/models/FindContactQueryParams.kt
+++ b/src/main/kotlin/com/nylas/models/FindContactQueryParams.kt
@@ -5,4 +5,42 @@ import com.squareup.moshi.Json
 data class FindContactQueryParams(
   @Json(name = "profile_picture")
   val profilePicture: Boolean? = null,
-) : IQueryParams
+  /**
+   * Specify fields that you want Nylas to return, as a comma-separated list (for example, select=id,updated_at).
+   * This allows you to receive only the portion of object data that you're interested in.
+   * You can use select to optimize response size and reduce latency by limiting queries to only the information that you need
+   */
+  @Json(name = "select")
+  var select: String? = null,
+) : IQueryParams {
+  /**
+   * Builder for [FindContactQueryParams].
+   */
+  class Builder {
+    private var profilePicture: Boolean? = null
+    private var select: String? = null
+
+    /**
+     * Sets whether to include profile picture.
+     * @param profilePicture Whether to include profile picture.
+     * @return The builder.
+     */
+    fun profilePicture(profilePicture: Boolean?) = apply { this.profilePicture = profilePicture }
+
+    /**
+     * Sets the fields to select.
+     * @param select The fields to select.
+     * @return The builder.
+     */
+    fun select(select: String?) = apply { this.select = select }
+
+    /**
+     * Builds the [FindContactQueryParams] object.
+     * @return The [FindContactQueryParams] object.
+     */
+    fun build() = FindContactQueryParams(
+      profilePicture = profilePicture,
+      select = select,
+    )
+  }
+}
diff --git a/src/main/kotlin/com/nylas/models/FindEventQueryParams.kt b/src/main/kotlin/com/nylas/models/FindEventQueryParams.kt
index 4e739f9f..da862fb6 100644
--- a/src/main/kotlin/com/nylas/models/FindEventQueryParams.kt
+++ b/src/main/kotlin/com/nylas/models/FindEventQueryParams.kt
@@ -11,6 +11,13 @@ data class FindEventQueryParams(
    */
   @Json(name = "calendar_id")
   val calendarId: String,
+  /**
+   * Specify fields that you want Nylas to return, as a comma-separated list (for example, select=id,updated_at).
+   * This allows you to receive only the portion of object data that you're interested in.
+   * You can use select to optimize response size and reduce latency by limiting queries to only the information that you need
+   */
+  @Json(name = "select")
+  var select: String? = null,
 ) : IQueryParams {
   /**
    * Builder for [FindEventQueryParams].
@@ -19,12 +26,22 @@ data class FindEventQueryParams(
   data class Builder(
     private val calendarId: String,
   ) {
+    private var select: String? = null
+
+    /**
+     * Sets the fields to select.
+     * @param select The fields to select.
+     * @return The builder.
+     */
+    fun select(select: String?) = apply { this.select = select }
+
     /**
      * Builds a new [FindEventQueryParams] instance.
      * @return [FindEventQueryParams]
      */
     fun build() = FindEventQueryParams(
       calendarId,
+      select,
     )
   }
 }
diff --git a/src/main/kotlin/com/nylas/models/FindFolderQueryParams.kt b/src/main/kotlin/com/nylas/models/FindFolderQueryParams.kt
new file mode 100644
index 00000000..6ed83371
--- /dev/null
+++ b/src/main/kotlin/com/nylas/models/FindFolderQueryParams.kt
@@ -0,0 +1,38 @@
+package com.nylas.models
+
+import com.squareup.moshi.Json
+
+/**
+ * Class representing the query parameters for finding a folder.
+ */
+data class FindFolderQueryParams(
+  /**
+   * Specify fields that you want Nylas to return, as a comma-separated list (for example, select=id,updated_at).
+   * This allows you to receive only the portion of object data that you're interested in.
+   * You can use select to optimize response size and reduce latency by limiting queries to only the information that you need
+   */
+  @Json(name = "select")
+  var select: String? = null,
+) : IQueryParams {
+  /**
+   * Builder for [FindFolderQueryParams].
+   */
+  class Builder {
+    private var select: String? = null
+
+    /**
+     * Sets the fields to select.
+     * @param select The fields to select.
+     * @return The builder.
+     */
+    fun select(select: String?) = apply { this.select = select }
+
+    /**
+     * Builds the [FindFolderQueryParams] object.
+     * @return The [FindFolderQueryParams] object.
+     */
+    fun build() = FindFolderQueryParams(
+      select = select,
+    )
+  }
+}
diff --git a/src/main/kotlin/com/nylas/models/FindMessageQueryParams.kt b/src/main/kotlin/com/nylas/models/FindMessageQueryParams.kt
index a2e5936e..68b5683a 100644
--- a/src/main/kotlin/com/nylas/models/FindMessageQueryParams.kt
+++ b/src/main/kotlin/com/nylas/models/FindMessageQueryParams.kt
@@ -11,12 +11,20 @@ data class FindMessageQueryParams(
    */
   @Json(name = "fields")
   val fields: MessageFields? = null,
+  /**
+   * Specify fields that you want Nylas to return, as a comma-separated list (for example, select=id,updated_at).
+   * This allows you to receive only the portion of object data that you're interested in.
+   * You can use select to optimize response size and reduce latency by limiting queries to only the information that you need
+   */
+  @Json(name = "select")
+  var select: String? = null,
 ) : IQueryParams {
   /**
    * Builder for [FindMessageQueryParams].
    */
   class Builder {
     private var fields: MessageFields? = null
+    private var select: String? = null
 
     /**
      * Set the fields to include in the response.
@@ -25,12 +33,20 @@ data class FindMessageQueryParams(
      */
     fun fields(fields: MessageFields?) = apply { this.fields = fields }
 
+    /**
+     * Set the fields to return in the response.
+     * @param select List of field names to return (e.g. "id,grant_id,subject")
+     * @return The builder.
+     */
+    fun select(select: String?) = apply { this.select = select }
+
     /**
      * Builds the [FindMessageQueryParams] object.
      * @return The [FindMessageQueryParams] object.
      */
     fun build() = FindMessageQueryParams(
       fields = fields,
+      select = select,
     )
   }
 }
diff --git a/src/main/kotlin/com/nylas/models/FindThreadQueryParams.kt b/src/main/kotlin/com/nylas/models/FindThreadQueryParams.kt
new file mode 100644
index 00000000..61d8a741
--- /dev/null
+++ b/src/main/kotlin/com/nylas/models/FindThreadQueryParams.kt
@@ -0,0 +1,38 @@
+package com.nylas.models
+
+import com.squareup.moshi.Json
+
+/**
+ * Class representing the query parameters for finding a thread.
+ */
+data class FindThreadQueryParams(
+  /**
+   * Specify fields that you want Nylas to return, as a comma-separated list (for example, select=id,updated_at).
+   * This allows you to receive only the portion of object data that you're interested in.
+   * You can use select to optimize response size and reduce latency by limiting queries to only the information that you need
+   */
+  @Json(name = "select")
+  var select: String? = null,
+) : IQueryParams {
+  /**
+   * Builder for [FindThreadQueryParams].
+   */
+  class Builder {
+    private var select: String? = null
+
+    /**
+     * Sets the fields to select.
+     * @param select The fields to select.
+     * @return The builder.
+     */
+    fun select(select: String?) = apply { this.select = select }
+
+    /**
+     * Builds the [FindThreadQueryParams] object.
+     * @return The [FindThreadQueryParams] object.
+     */
+    fun build() = FindThreadQueryParams(
+      select = select,
+    )
+  }
+}
diff --git a/src/main/kotlin/com/nylas/models/Folder.kt b/src/main/kotlin/com/nylas/models/Folder.kt
index bcac524d..41b70b03 100644
--- a/src/main/kotlin/com/nylas/models/Folder.kt
+++ b/src/main/kotlin/com/nylas/models/Folder.kt
@@ -10,12 +10,12 @@ data class Folder(
    * A globally unique object identifier.
    */
   @Json(name = "id")
-  val id: String,
+  val id: String? = null,
   /**
    * A Grant ID of the Nylas account.
    */
   @Json(name = "grant_id")
-  val grantId: String,
+  val grantId: String? = null,
   /**
    * Folder name
    */
diff --git a/src/main/kotlin/com/nylas/models/ListCalendersQueryParams.kt b/src/main/kotlin/com/nylas/models/ListCalendersQueryParams.kt
index 9adaf03c..b6a2f857 100644
--- a/src/main/kotlin/com/nylas/models/ListCalendersQueryParams.kt
+++ b/src/main/kotlin/com/nylas/models/ListCalendersQueryParams.kt
@@ -23,6 +23,13 @@ data class ListCalendersQueryParams(
    */
   @Json(name = "metadata_pair")
   val metadataPair: Map<String, String>? = null,
+  /**
+   * Specify fields that you want Nylas to return, as a comma-separated list (for example, select=id,updated_at).
+   * This allows you to receive only the portion of object data that you're interested in.
+   * You can use select to optimize response size and reduce latency by limiting queries to only the information that you need
+   */
+  @Json(name = "select")
+  var select: String? = null,
 ) : IQueryParams {
   /**
    * Builder for [ListCalendersQueryParams].
@@ -31,6 +38,7 @@ data class ListCalendersQueryParams(
     private var limit: Int? = null
     private var pageToken: String? = null
     private var metadataPair: Map<String, String>? = null
+    private var select: String? = null
 
     /**
      * Sets the maximum number of objects to return.
@@ -55,6 +63,13 @@ data class ListCalendersQueryParams(
      */
     fun metadataPair(metadataPair: Map<String, String>?) = apply { this.metadataPair = metadataPair }
 
+    /**
+     * Set the fields to return in the response.
+     * @param select List of field names to return (e.g. "id,grant_id,name")
+     * @return The builder.
+     */
+    fun select(select: String?) = apply { this.select = select }
+
     /**
      * Builds a [ListCalendersQueryParams] instance.
      * @return The [ListCalendersQueryParams] instance.
@@ -63,6 +78,7 @@ data class ListCalendersQueryParams(
       limit,
       pageToken,
       metadataPair,
+      select,
     )
   }
 }
diff --git a/src/main/kotlin/com/nylas/models/ListContactsQueryParams.kt b/src/main/kotlin/com/nylas/models/ListContactsQueryParams.kt
index ed832d44..b00fca27 100644
--- a/src/main/kotlin/com/nylas/models/ListContactsQueryParams.kt
+++ b/src/main/kotlin/com/nylas/models/ListContactsQueryParams.kt
@@ -44,6 +44,13 @@ data class ListContactsQueryParams(
    */
   @Json(name = "recurse")
   val recurse: Boolean? = null,
+  /**
+   * Specify fields that you want Nylas to return, as a comma-separated list (for example, select=id,updated_at).
+   * This allows you to receive only the portion of object data that you're interested in.
+   * You can use select to optimize response size and reduce latency by limiting queries to only the information that you need
+   */
+  @Json(name = "select")
+  var select: String? = null,
 ) : IQueryParams {
   class Builder {
     private var limit: Int? = null
@@ -53,6 +60,7 @@ data class ListContactsQueryParams(
     private var source: SourceType? = null
     private var group: String? = null
     private var recurse: Boolean? = null
+    private var select: String? = null
 
     /**
      * Sets the maximum number of objects to return.
@@ -106,6 +114,13 @@ data class ListContactsQueryParams(
      */
     fun recurse(recurse: Boolean?) = apply { this.recurse = recurse }
 
+    /**
+     * Set the fields to return in the response.
+     * @param select List of field names to return (e.g. "id,grant_id,display_name")
+     * @return The builder.
+     */
+    fun select(select: String?) = apply { this.select = select }
+
     /**
      * Builds a [ListContactsQueryParams] instance.
      * @return The [ListContactsQueryParams] instance.
@@ -118,6 +133,7 @@ data class ListContactsQueryParams(
       source = source,
       group = group,
       recurse = recurse,
+      select = select,
     )
   }
 }
diff --git a/src/main/kotlin/com/nylas/models/ListEventQueryParams.kt b/src/main/kotlin/com/nylas/models/ListEventQueryParams.kt
index 3b7f81ec..a663aa21 100644
--- a/src/main/kotlin/com/nylas/models/ListEventQueryParams.kt
+++ b/src/main/kotlin/com/nylas/models/ListEventQueryParams.kt
@@ -124,6 +124,13 @@ data class ListEventQueryParams(
    */
   @Json(name = "event_type")
   val eventType: EventType? = null,
+  /**
+   * Specify fields that you want Nylas to return, as a comma-separated list (for example, select=id,updated_at).
+   * This allows you to receive only the portion of object data that you're interested in.
+   * You can use select to optimize response size and reduce latency by limiting queries to only the information that you need
+   */
+  @Json(name = "select")
+  var select: String? = null,
 ) : IQueryParams {
   /**
    * Builder for [ListEventQueryParams].
@@ -152,6 +159,7 @@ data class ListEventQueryParams(
     private var updatedAfter: Long? = null
     private var attendees: List<String>? = null
     private var eventType: EventType? = null
+    private var select: String? = null
 
     /**
      * Sets the maximum number of objects to return.
@@ -299,6 +307,13 @@ data class ListEventQueryParams(
      */
     fun eventType(eventType: EventType?) = apply { this.eventType = eventType }
 
+    /**
+     * Set the fields to return in the response.
+     * @param select List of field names to return (e.g. "id,grant_id,title")
+     * @return The builder.
+     */
+    fun select(select: String?) = apply { this.select = select }
+
     /**
      * Builds a [ListEventQueryParams] instance.
      * @return The [ListEventQueryParams] instance.
@@ -323,6 +338,7 @@ data class ListEventQueryParams(
       updatedAfter,
       attendees,
       eventType,
+      select,
     )
   }
 }
diff --git a/src/main/kotlin/com/nylas/models/ListMessagesQueryParams.kt b/src/main/kotlin/com/nylas/models/ListMessagesQueryParams.kt
index 2f1f75df..0d92f94e 100644
--- a/src/main/kotlin/com/nylas/models/ListMessagesQueryParams.kt
+++ b/src/main/kotlin/com/nylas/models/ListMessagesQueryParams.kt
@@ -94,6 +94,13 @@ data class ListMessagesQueryParams(
    */
   @Json(name = "search_query_native")
   val searchQueryNative: String? = null,
+  /**
+   * Specify fields that you want Nylas to return, as a comma-separated list (for example, select=id,updated_at).
+   * This allows you to receive only the portion of object data that you're interested in.
+   * You can use select to optimize response size and reduce latency by limiting queries to only the information that you need
+   */
+  @Json(name = "select")
+  var select: String? = null,
 ) : IQueryParams {
   class Builder {
     private var limit: Int? = null
@@ -113,6 +120,7 @@ data class ListMessagesQueryParams(
     private var hasAttachment: Boolean? = null
     private var fields: MessageFields? = null
     private var searchQueryNative: String? = null
+    private var select: String? = null
 
     /**
      * Sets the maximum number of objects to return.
@@ -236,6 +244,13 @@ data class ListMessagesQueryParams(
      */
     fun searchQueryNative(searchQueryNative: String?) = apply { this.searchQueryNative = searchQueryNative }
 
+    /**
+     * Set the fields to return in the response.
+     * @param select List of field names to return (e.g. "id,grant_id,subject")
+     * @return The builder
+     */
+    fun select(select: String?) = apply { this.select = select }
+
     /**
      * Builds the [ListMessagesQueryParams] object.
      * @return The [ListMessagesQueryParams] object.
@@ -258,6 +273,7 @@ data class ListMessagesQueryParams(
       hasAttachment = hasAttachment,
       fields = fields,
       searchQueryNative = searchQueryNative,
+      select = select,
     )
   }
 }
diff --git a/src/main/kotlin/com/nylas/models/ListThreadsQueryParams.kt b/src/main/kotlin/com/nylas/models/ListThreadsQueryParams.kt
index 60f5b93b..2da2719e 100644
--- a/src/main/kotlin/com/nylas/models/ListThreadsQueryParams.kt
+++ b/src/main/kotlin/com/nylas/models/ListThreadsQueryParams.kt
@@ -88,6 +88,13 @@ data class ListThreadsQueryParams(
    */
   @Json(name = "search_query_native")
   val searchQueryNative: String? = null,
+  /**
+   * Specify fields that you want Nylas to return, as a comma-separated list (for example, select=id,updated_at).
+   * This allows you to receive only the portion of object data that you're interested in.
+   * You can use select to optimize response size and reduce latency by limiting queries to only the information that you need
+   */
+  @Json(name = "select")
+  var select: String? = null,
 ) : IQueryParams {
 
   /**
@@ -129,6 +136,7 @@ data class ListThreadsQueryParams(
     private var hasAttachment: Boolean? = null
     private var fields: MessageFields? = null
     private var searchQueryNative: String? = null
+    private var select: String? = null
 
     /**
      * Sets the maximum number of objects to return.
@@ -270,6 +278,13 @@ data class ListThreadsQueryParams(
      */
     fun searchQueryNative(searchQueryNative: String?) = apply { this.searchQueryNative = searchQueryNative }
 
+    /**
+     * Set the fields to return in the response.
+     * @param select List of field names to return (e.g. "id,grant_id,subject")
+     * @return The builder
+     */
+    fun select(select: String?) = apply { this.select = select }
+
     /**
      * Builds the [ListThreadsQueryParams] object.
      * @return The [ListThreadsQueryParams] object.
@@ -290,6 +305,7 @@ data class ListThreadsQueryParams(
       latestMessageAfter = latestMessageAfter,
       hasAttachment = hasAttachment,
       searchQueryNative = searchQueryNative,
+      select = select,
     )
   }
 }
diff --git a/src/main/kotlin/com/nylas/models/Message.kt b/src/main/kotlin/com/nylas/models/Message.kt
index cf794a48..ec1099ce 100644
--- a/src/main/kotlin/com/nylas/models/Message.kt
+++ b/src/main/kotlin/com/nylas/models/Message.kt
@@ -10,7 +10,7 @@ data class Message(
    * Grant ID of the Nylas account.
    */
   @Json(name = "grant_id")
-  val grantId: String,
+  val grantId: String? = null,
   /**
    * The type of object.
    */
diff --git a/src/main/kotlin/com/nylas/models/Thread.kt b/src/main/kotlin/com/nylas/models/Thread.kt
index f6add67d..b77e483a 100644
--- a/src/main/kotlin/com/nylas/models/Thread.kt
+++ b/src/main/kotlin/com/nylas/models/Thread.kt
@@ -7,12 +7,12 @@ data class Thread(
    * The unique identifier for the thread.
    */
   @Json(name = "id")
-  val id: String,
+  val id: String? = null,
   /**
    * Grant ID of the Nylas account.
    */
   @Json(name = "grant_id")
-  val grantId: String,
+  val grantId: String? = null,
   /**
    * The type of object.
    */
diff --git a/src/main/kotlin/com/nylas/resources/Calendars.kt b/src/main/kotlin/com/nylas/resources/Calendars.kt
index 6572e261..c474d96f 100644
--- a/src/main/kotlin/com/nylas/resources/Calendars.kt
+++ b/src/main/kotlin/com/nylas/resources/Calendars.kt
@@ -33,14 +33,15 @@ class Calendars(client: NylasClient) : Resource<Calendar>(client, Calendar::clas
    * Return a Calendar
    * @param identifier Grant ID or email account to query.
    * @param calendarId The id of the Calendar to retrieve. Use "primary" to refer to the primary calendar associated with grant.
+   * @param queryParams The query parameters to include in the request
    * @param overrides Optional request overrides to apply
    * @return The calendar
    */
   @Throws(NylasApiError::class, NylasSdkTimeoutError::class)
   @JvmOverloads
-  fun find(identifier: String, calendarId: String, overrides: RequestOverrides? = null): Response<Calendar> {
+  fun find(identifier: String, calendarId: String, queryParams: FindCalendarQueryParams? = null, overrides: RequestOverrides? = null): Response<Calendar> {
     val path = String.format("v3/grants/%s/calendars/%s", identifier, calendarId)
-    return findResource(path, overrides = overrides)
+    return findResource(path, queryParams, overrides = overrides)
   }
 
   /**
diff --git a/src/main/kotlin/com/nylas/resources/Folders.kt b/src/main/kotlin/com/nylas/resources/Folders.kt
index 31bfae3b..93c44151 100644
--- a/src/main/kotlin/com/nylas/resources/Folders.kt
+++ b/src/main/kotlin/com/nylas/resources/Folders.kt
@@ -23,14 +23,15 @@ class Folders(client: NylasClient) : Resource<Folder>(client, Folder::class.java
    * Return a Folder
    * @param identifier Grant ID or email account to query.
    * @param folderId The id of the folder to retrieve.
+   * @param queryParams The query parameters to include in the request
    * @param overrides Optional request overrides to apply
    * @return The folder
    */
   @Throws(NylasApiError::class, NylasSdkTimeoutError::class)
   @JvmOverloads
-  fun find(identifier: String, folderId: String, overrides: RequestOverrides? = null): Response<Folder> {
+  fun find(identifier: String, folderId: String, queryParams: FindFolderQueryParams? = null, overrides: RequestOverrides? = null): Response<Folder> {
     val path = String.format("v3/grants/%s/folders/%s", identifier, folderId)
-    return findResource(path, overrides = overrides)
+    return findResource(path, queryParams, overrides = overrides)
   }
 
   /**
diff --git a/src/main/kotlin/com/nylas/resources/Threads.kt b/src/main/kotlin/com/nylas/resources/Threads.kt
index 020fc208..574a191f 100644
--- a/src/main/kotlin/com/nylas/resources/Threads.kt
+++ b/src/main/kotlin/com/nylas/resources/Threads.kt
@@ -23,14 +23,15 @@ class Threads(client: NylasClient) : Resource<Thread>(client, Thread::class.java
    * Return a Thread
    * @param identifier The identifier of the grant to act upon
    * @param threadId The id of the Thread to retrieve.
+   * @param queryParams The query parameters to include in the request
    * @param overrides Optional request overrides to apply
    * @return The Thread
    */
   @Throws(NylasApiError::class, NylasSdkTimeoutError::class)
   @JvmOverloads
-  fun find(identifier: String, threadId: String, overrides: RequestOverrides? = null): Response<Thread> {
+  fun find(identifier: String, threadId: String, queryParams: FindThreadQueryParams? = null, overrides: RequestOverrides? = null): Response<Thread> {
     val path = String.format("v3/grants/%s/threads/%s", identifier, threadId)
-    return findResource(path, overrides = overrides)
+    return findResource(path, queryParams, overrides = overrides)
   }
 
   /**
diff --git a/src/test/kotlin/com/nylas/models/SelectParameterDeserializationTests.kt b/src/test/kotlin/com/nylas/models/SelectParameterDeserializationTests.kt
new file mode 100644
index 00000000..dbff0a0e
--- /dev/null
+++ b/src/test/kotlin/com/nylas/models/SelectParameterDeserializationTests.kt
@@ -0,0 +1,212 @@
+package com.nylas.models
+
+import com.nylas.util.JsonHelper
+import okio.Buffer
+import org.junit.jupiter.api.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertIs
+import kotlin.test.assertNull
+
+/**
+ * Tests to verify that models can be deserialized properly when using the select parameter,
+ * which means some fields may be missing from the response JSON.
+ */
+class SelectParameterDeserializationTests {
+
+  @Test
+  fun `Folder deserializes properly with minimal select fields (id only)`() {
+    val adapter = JsonHelper.moshi().adapter(Folder::class.java)
+    val jsonBuffer = Buffer().writeUtf8(
+      """
+      {
+        "id": "folder-123",
+        "object": "folder"
+      }
+      """.trimIndent(),
+    )
+
+    val folder = adapter.fromJson(jsonBuffer)!!
+    assertIs<Folder>(folder)
+    assertEquals("folder-123", folder.id)
+    assertEquals("folder", folder.obj)
+    assertNull(folder.grantId) // Should be null when not included in select
+    assertNull(folder.name)
+  }
+
+  @Test
+  fun `Folder deserializes properly with select id,name (no grant_id)`() {
+    val adapter = JsonHelper.moshi().adapter(Folder::class.java)
+    val jsonBuffer = Buffer().writeUtf8(
+      """
+      {
+        "id": "folder-123",
+        "name": "Inbox",
+        "object": "folder"
+      }
+      """.trimIndent(),
+    )
+
+    val folder = adapter.fromJson(jsonBuffer)!!
+    assertIs<Folder>(folder)
+    assertEquals("folder-123", folder.id)
+    assertEquals("Inbox", folder.name)
+    assertEquals("folder", folder.obj)
+    assertNull(folder.grantId) // Should be null when not included in select
+  }
+
+  @Test
+  fun `Contact deserializes properly with minimal select fields (id only)`() {
+    val adapter = JsonHelper.moshi().adapter(Contact::class.java)
+    val jsonBuffer = Buffer().writeUtf8(
+      """
+      {
+        "id": "contact-123",
+        "object": "contact"
+      }
+      """.trimIndent(),
+    )
+
+    val contact = adapter.fromJson(jsonBuffer)!!
+    assertIs<Contact>(contact)
+    assertEquals("contact-123", contact.id)
+    assertNull(contact.grantId) // Should be null when not included in select
+    assertNull(contact.displayName)
+  }
+
+  @Test
+  fun `Message deserializes properly with minimal select fields (id only)`() {
+    val adapter = JsonHelper.moshi().adapter(Message::class.java)
+    val jsonBuffer = Buffer().writeUtf8(
+      """
+      {
+        "id": "message-123",
+        "object": "message"
+      }
+      """.trimIndent(),
+    )
+
+    val message = adapter.fromJson(jsonBuffer)!!
+    assertIs<Message>(message)
+    assertEquals("message-123", message.id)
+    assertNull(message.grantId) // Should be null when not included in select
+    assertNull(message.subject)
+  }
+
+  @Test
+  fun `Thread deserializes properly with minimal select fields (id only)`() {
+    val adapter = JsonHelper.moshi().adapter(Thread::class.java)
+    val jsonBuffer = Buffer().writeUtf8(
+      """
+      {
+        "id": "thread-123",
+        "object": "thread"
+      }
+      """.trimIndent(),
+    )
+
+    val thread = adapter.fromJson(jsonBuffer)!!
+    assertIs<Thread>(thread)
+    assertEquals("thread-123", thread.id)
+    assertNull(thread.grantId) // Should be null when not included in select
+    assertNull(thread.subject)
+  }
+
+  @Test
+  fun `Event deserializes properly with minimal select fields (id only)`() {
+    val adapter = JsonHelper.moshi().adapter(Event::class.java)
+    val jsonBuffer = Buffer().writeUtf8(
+      """
+      {
+        "id": "event-123",
+        "object": "event"
+      }
+      """.trimIndent(),
+    )
+
+    val event = adapter.fromJson(jsonBuffer)!!
+    assertIs<Event>(event)
+    assertEquals("event-123", event.id)
+    assertNull(event.grantId) // Should be null when not included in select
+    assertNull(event.title)
+  }
+
+  @Test
+  fun `Calendar deserializes properly with minimal select fields (id only)`() {
+    val adapter = JsonHelper.moshi().adapter(Calendar::class.java)
+    val jsonBuffer = Buffer().writeUtf8(
+      """
+      {
+        "id": "calendar-123",
+        "object": "calendar"
+      }
+      """.trimIndent(),
+    )
+
+    val calendar = adapter.fromJson(jsonBuffer)!!
+    assertIs<Calendar>(calendar)
+    assertEquals("calendar-123", calendar.id)
+    assertNull(calendar.grantId) // Should be null when not included in select
+    assertNull(calendar.name)
+  }
+
+  @Test
+  fun `Attachment deserializes properly with minimal select fields (id only)`() {
+    val adapter = JsonHelper.moshi().adapter(Attachment::class.java)
+    val jsonBuffer = Buffer().writeUtf8(
+      """
+      {
+        "id": "attachment-123",
+        "object": "attachment"
+      }
+      """.trimIndent(),
+    )
+
+    val attachment = adapter.fromJson(jsonBuffer)!!
+    assertIs<Attachment>(attachment)
+    assertEquals("attachment-123", attachment.id)
+    assertNull(attachment.grantId) // Should be null when not included in select
+    assertNull(attachment.filename)
+  }
+
+  @Test
+  fun `ListResponse with Folder array deserializes properly with select fields`() {
+    val listResponseType = com.squareup.moshi.Types.newParameterizedType(
+      ListResponse::class.java,
+      Folder::class.java,
+    )
+    val adapter = JsonHelper.moshi().adapter<ListResponse<Folder>>(listResponseType)
+    val jsonBuffer = Buffer().writeUtf8(
+      """
+      {
+        "data": [
+          {
+            "id": "folder-1",
+            "name": "Inbox",
+            "object": "folder"
+          },
+          {
+            "id": "folder-2",
+            "name": "Sent",
+            "object": "folder"
+          }
+        ],
+        "next_cursor": "abc123"
+      }
+      """.trimIndent(),
+    )
+
+    val response = adapter.fromJson(jsonBuffer)!!
+    assertIs<ListResponse<Folder>>(response)
+    assertEquals(2, response.data.size)
+
+    val folder1 = response.data[0]
+    assertEquals("folder-1", folder1.id)
+    assertEquals("Inbox", folder1.name)
+    assertNull(folder1.grantId) // Should be null when not in select
+
+    val folder2 = response.data[1]
+    assertEquals("folder-2", folder2.id)
+    assertEquals("Sent", folder2.name)
+    assertNull(folder2.grantId) // Should be null when not in select
+  }
+}
diff --git a/src/test/kotlin/com/nylas/resources/EventsTests.kt b/src/test/kotlin/com/nylas/resources/EventsTests.kt
index d343fed6..11789378 100644
--- a/src/test/kotlin/com/nylas/resources/EventsTests.kt
+++ b/src/test/kotlin/com/nylas/resources/EventsTests.kt
@@ -140,12 +140,12 @@ class EventsTests {
       assertEquals("event", event.getObject())
       assertEquals("organizer@example.com", event.organizer?.email)
       assertEquals("", event.organizer?.name)
-      assertEquals(1, event.participants.size)
-      assertEquals("Aristotle", event.participants[0].comment)
-      assertEquals("aristotle@example.com", event.participants[0].email)
-      assertEquals("Aristotle", event.participants[0].name)
-      assertEquals("+1 23456778", event.participants[0].phoneNumber)
-      assertEquals(ParticipantStatus.MAYBE, event.participants[0].status)
+      assertEquals(1, event.participants?.size)
+      assertEquals("Aristotle", event.participants?.get(0)?.comment)
+      assertEquals("aristotle@example.com", event.participants?.get(0)?.email)
+      assertEquals("Aristotle", event.participants?.get(0)?.name)
+      assertEquals("+1 23456778", event.participants?.get(0)?.phoneNumber)
+      assertEquals(ParticipantStatus.MAYBE, event.participants?.get(0)?.status)
       assertEquals(false, event.readOnly)
       assertEquals(false, event.reminders?.useDefault)
       assertEquals(1, event.reminders?.overrides?.size)
diff --git a/src/test/kotlin/com/nylas/resources/FoldersTests.kt b/src/test/kotlin/com/nylas/resources/FoldersTests.kt
index 3c12f845..b6557331 100644
--- a/src/test/kotlin/com/nylas/resources/FoldersTests.kt
+++ b/src/test/kotlin/com/nylas/resources/FoldersTests.kt
@@ -75,6 +75,49 @@ class FoldersTests {
       assertEquals(0, folder.totalCount)
       assertEquals(listOf("\\SENT"), folder.attributes)
     }
+
+    @Test
+    fun `Folder with select parameter serializes properly with only selected fields`() {
+      val adapter = JsonHelper.moshi().adapter(Folder::class.java)
+      val jsonBuffer = Buffer().writeUtf8(
+        """
+          {
+            "id": "SENT",
+            "name": "SENT"
+          }
+        """.trimIndent(),
+      )
+
+      val folder = adapter.fromJson(jsonBuffer)!!
+      assertIs<Folder>(folder)
+      assertEquals("SENT", folder.id)
+      assertEquals("SENT", folder.name)
+      // When select is used, grantId and other fields may not be present
+      assertNull(folder.grantId)
+      assertEquals("folder", folder.getObject()) // default value
+    }
+
+    @Test
+    fun `Folder backwards compatibility - full object still works`() {
+      val adapter = JsonHelper.moshi().adapter(Folder::class.java)
+      val jsonBuffer = Buffer().writeUtf8(
+        """
+          {
+            "id": "SENT",
+            "grant_id": "41009df5-bf11-4c97-aa18-b285b5f2e386",
+            "name": "SENT",
+            "object": "folder"
+          }
+        """.trimIndent(),
+      )
+
+      val folder = adapter.fromJson(jsonBuffer)!!
+      assertIs<Folder>(folder)
+      assertEquals("SENT", folder.id)
+      assertEquals("41009df5-bf11-4c97-aa18-b285b5f2e386", folder.grantId)
+      assertEquals("SENT", folder.name)
+      assertEquals("folder", folder.getObject())
+    }
   }
 
   @Nested
@@ -305,6 +348,29 @@ class FoldersTests {
       assertNull(queryParamCaptor.firstValue)
     }
 
+    @Test
+    fun `finding a folder with select parameter calls requests with the correct params`() {
+      val folderId = "folder-123"
+      val queryParams = FindFolderQueryParams(select = "id,name")
+
+      folders.find(grantId, folderId, queryParams)
+
+      val pathCaptor = argumentCaptor<String>()
+      val typeCaptor = argumentCaptor<Type>()
+      val queryParamCaptor = argumentCaptor<IQueryParams>()
+      val overrideParamCaptor = argumentCaptor<RequestOverrides>()
+      verify(mockNylasClient).executeGet<ListResponse<Folder>>(
+        pathCaptor.capture(),
+        typeCaptor.capture(),
+        queryParamCaptor.capture(),
+        overrideParamCaptor.capture(),
+      )
+
+      assertEquals("v3/grants/$grantId/folders/$folderId", pathCaptor.firstValue)
+      assertEquals(Types.newParameterizedType(Response::class.java, Folder::class.java), typeCaptor.firstValue)
+      assertEquals(queryParams, queryParamCaptor.firstValue)
+    }
+
     @Test
     fun `creating a folder calls requests with the correct params`() {
       val adapter = JsonHelper.moshi().adapter(CreateFolderRequest::class.java)
diff --git a/src/test/kotlin/com/nylas/resources/SelectParameterIntegrationTests.kt b/src/test/kotlin/com/nylas/resources/SelectParameterIntegrationTests.kt
new file mode 100644
index 00000000..c369c033
--- /dev/null
+++ b/src/test/kotlin/com/nylas/resources/SelectParameterIntegrationTests.kt
@@ -0,0 +1,124 @@
+package com.nylas.resources
+
+import com.nylas.NylasClient
+import com.nylas.models.*
+import okhttp3.*
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import org.mockito.kotlin.*
+import kotlin.test.*
+
+/**
+ * Integration tests to verify that select parameter functionality works end-to-end,
+ * focusing on the response parsing and URL construction.
+ */
+class SelectParameterIntegrationTests {
+
+  private lateinit var grantId: String
+  private lateinit var mockNylasClient: NylasClient
+
+  @BeforeEach
+  fun setup() {
+    grantId = "abc-123-grant-id"
+    mockNylasClient = mock<NylasClient>()
+  }
+
+  @Test
+  fun `list folders with select parameter includes correct query params`() {
+    val folders = Folders(mockNylasClient)
+    val queryParams = ListFoldersQueryParams(
+      limit = 10,
+      select = "id,name",
+    )
+
+    folders.list(grantId, queryParams)
+
+    val pathCaptor = argumentCaptor<String>()
+    val typeCaptor = argumentCaptor<java.lang.reflect.Type>()
+    val queryParamCaptor = argumentCaptor<IQueryParams>()
+    val overrideParamCaptor = argumentCaptor<RequestOverrides>()
+
+    verify(mockNylasClient).executeGet<ListResponse<Folder>>(
+      pathCaptor.capture(),
+      typeCaptor.capture(),
+      queryParamCaptor.capture(),
+      overrideParamCaptor.capture(),
+    )
+
+    assertEquals("v3/grants/$grantId/folders", pathCaptor.firstValue)
+    assertEquals(queryParams, queryParamCaptor.firstValue)
+    assertEquals("id,name", (queryParamCaptor.firstValue as ListFoldersQueryParams).select)
+  }
+
+  @Test
+  fun `find folder with select parameter includes correct query params`() {
+    val folders = Folders(mockNylasClient)
+    val queryParams = FindFolderQueryParams(select = "id,name")
+
+    folders.find(grantId, "folder-123", queryParams)
+
+    val pathCaptor = argumentCaptor<String>()
+    val typeCaptor = argumentCaptor<java.lang.reflect.Type>()
+    val queryParamCaptor = argumentCaptor<IQueryParams>()
+    val overrideParamCaptor = argumentCaptor<RequestOverrides>()
+
+    verify(mockNylasClient).executeGet<com.nylas.models.Response<Folder>>(
+      pathCaptor.capture(),
+      typeCaptor.capture(),
+      queryParamCaptor.capture(),
+      overrideParamCaptor.capture(),
+    )
+
+    assertEquals("v3/grants/$grantId/folders/folder-123", pathCaptor.firstValue)
+    assertEquals(queryParams, queryParamCaptor.firstValue)
+    assertEquals("id,name", (queryParamCaptor.firstValue as FindFolderQueryParams).select)
+  }
+
+  @Test
+  fun `list contacts with select parameter includes correct query params`() {
+    val contacts = Contacts(mockNylasClient)
+    val queryParams = ListContactsQueryParams(
+      limit = 10,
+      select = "id,display_name",
+    )
+
+    contacts.list(grantId, queryParams)
+
+    val pathCaptor = argumentCaptor<String>()
+    val queryParamCaptor = argumentCaptor<IQueryParams>()
+
+    verify(mockNylasClient).executeGet<ListResponse<Contact>>(
+      pathCaptor.capture(),
+      any(),
+      queryParamCaptor.capture(),
+      any(),
+    )
+
+    assertEquals("v3/grants/$grantId/contacts", pathCaptor.firstValue)
+    assertEquals("id,display_name", (queryParamCaptor.firstValue as ListContactsQueryParams).select)
+  }
+
+  @Test
+  fun `list messages with select parameter includes correct query params`() {
+    val messages = Messages(mockNylasClient)
+    val queryParams = ListMessagesQueryParams(
+      limit = 10,
+      select = "id,subject",
+    )
+
+    messages.list(grantId, queryParams)
+
+    val pathCaptor = argumentCaptor<String>()
+    val queryParamCaptor = argumentCaptor<IQueryParams>()
+
+    verify(mockNylasClient).executeGet<ListResponse<Message>>(
+      pathCaptor.capture(),
+      any(),
+      queryParamCaptor.capture(),
+      any(),
+    )
+
+    assertEquals("v3/grants/$grantId/messages", pathCaptor.firstValue)
+    assertEquals("id,subject", (queryParamCaptor.firstValue as ListMessagesQueryParams).select)
+  }
+}