diff --git a/docs/syntax.md b/docs/syntax.md
index 85591dc..7190942 100644
--- a/docs/syntax.md
+++ b/docs/syntax.md
@@ -274,6 +274,44 @@ parser.evaluate('toUpper(trim(left("  hello world  ", 10)))'); // "HELLO WOR"
 
 > **Note:** All string functions return `undefined` if any of their required arguments are `undefined`, allowing for safe chaining and conditional logic.
 
+## Object Manipulation Functions
+
+The parser includes functions for working with objects.
+
+| Function              | Description |
+|:--------------------- |:----------- |
+| merge(obj1, obj2, ...)| Merges two or more objects together. Duplicate keys are overwritten by later arguments. |
+| keys(obj)             | Returns an array of strings containing the keys of the object. |
+| values(obj)           | Returns an array containing the values of the object. |
+| flatten(obj, sep?)    | Flattens a nested object's keys using an optional separator (default: `_`). For example, `{foo: {bar: 1}}` becomes `{foo_bar: 1}`. |
+
+### Object Function Examples
+
+```js
+const parser = new Parser();
+
+// Merge objects
+parser.evaluate('merge({a: 1}, {b: 2})'); // {a: 1, b: 2}
+parser.evaluate('merge({a: 1, b: 2}, {b: 3, c: 4})'); // {a: 1, b: 3, c: 4}
+parser.evaluate('merge({a: 1}, {b: 2}, {c: 3})'); // {a: 1, b: 2, c: 3}
+
+// Get keys
+parser.evaluate('keys({a: 1, b: 2, c: 3})'); // ["a", "b", "c"]
+
+// Get values
+parser.evaluate('values({a: 1, b: 2, c: 3})'); // [1, 2, 3]
+
+// Flatten nested objects
+parser.evaluate('flatten(obj)', { obj: { foo: { bar: 1 } } }); // {foo_bar: 1}
+parser.evaluate('flatten(obj)', { obj: { a: { b: { c: 1 } } } }); // {a_b_c: 1}
+parser.evaluate('flatten(obj, ".")', { obj: { foo: { bar: 1 } } }); // {"foo.bar": 1}
+
+// Mixed nested and flat keys
+parser.evaluate('flatten(obj)', { obj: { a: 1, b: { c: 2 } } }); // {a: 1, b_c: 2}
+```
+
+> **Note:** All object functions return `undefined` if any of their required arguments are `undefined`, allowing for safe chaining and conditional logic.
+
 ## Array Literals
 
 Arrays can be created by including the elements inside square `[]` brackets, separated by commas. For example:
diff --git a/src/functions/index.ts b/src/functions/index.ts
index 4f6a8fd..a9f8510 100644
--- a/src/functions/index.ts
+++ b/src/functions/index.ts
@@ -7,3 +7,4 @@ export * from './math';
 export * from './array';
 export * from './utility';
 export * from './string';
+export * from './object';
diff --git a/src/functions/object/index.ts b/src/functions/object/index.ts
new file mode 100644
index 0000000..26d57dd
--- /dev/null
+++ b/src/functions/object/index.ts
@@ -0,0 +1,6 @@
+/**
+ * Object functions exports
+ * Re-exports all object manipulation functions
+ */
+
+export * from './operations.js';
diff --git a/src/functions/object/operations.ts b/src/functions/object/operations.ts
new file mode 100644
index 0000000..bdf2bbc
--- /dev/null
+++ b/src/functions/object/operations.ts
@@ -0,0 +1,102 @@
+/**
+ * Object manipulation functions
+ * Provides comprehensive object operations for the expression parser
+ */
+
+import { Value, ValueObject } from '../../types/values.js';
+
+/**
+ * Merges two or more objects together.
+ * Duplicate keys will be overwritten by later arguments.
+ * @param objects - Objects to merge
+ * @returns Merged object or undefined if any argument is undefined
+ */
+export function merge(...objects: (ValueObject | undefined)[]): ValueObject | undefined {
+  if (objects.length === 0) {
+    return {};
+  }
+
+  for (const obj of objects) {
+    if (obj === undefined) {
+      return undefined;
+    }
+    if (typeof obj !== 'object' || obj === null || Array.isArray(obj)) {
+      throw new Error('Arguments to merge must be objects');
+    }
+  }
+
+  return Object.assign({}, ...objects);
+}
+
+/**
+ * Returns an array of the keys of an object.
+ * @param obj - The object to get keys from
+ * @returns Array of string keys or undefined if input is undefined
+ */
+export function keys(obj: ValueObject | undefined): string[] | undefined {
+  if (obj === undefined) {
+    return undefined;
+  }
+  if (typeof obj !== 'object' || obj === null || Array.isArray(obj)) {
+    throw new Error('Argument to keys must be an object');
+  }
+  return Object.keys(obj);
+}
+
+/**
+ * Returns an array of the values of an object.
+ * @param obj - The object to get values from
+ * @returns Array of values or undefined if input is undefined
+ */
+export function values(obj: ValueObject | undefined): Value[] | undefined {
+  if (obj === undefined) {
+    return undefined;
+  }
+  if (typeof obj !== 'object' || obj === null || Array.isArray(obj)) {
+    throw new Error('Argument to values must be an object');
+  }
+  return Object.values(obj);
+}
+
+/**
+ * Flattens a nested object's keys using underscore as separator.
+ * For example: { foo: { bar: 1 } } becomes { foo_bar: 1 }
+ * @param obj - The object to flatten
+ * @param separator - The separator to use (default: '_')
+ * @returns Flattened object or undefined if input is undefined
+ */
+export function flatten(
+  obj: ValueObject | undefined,
+  separator: string = '_'
+): ValueObject | undefined {
+  if (obj === undefined) {
+    return undefined;
+  }
+  if (typeof obj !== 'object' || obj === null || Array.isArray(obj)) {
+    throw new Error('First argument to flatten must be an object');
+  }
+  if (typeof separator !== 'string') {
+    throw new Error('Second argument to flatten must be a string');
+  }
+
+  const result: ValueObject = {};
+
+  function flattenHelper(current: Value, prefix: string): void {
+    if (
+      current !== null &&
+      typeof current === 'object' &&
+      !Array.isArray(current)
+    ) {
+      for (const key of Object.keys(current as ValueObject)) {
+        const newKey = prefix ? `${prefix}${separator}${key}` : key;
+        flattenHelper((current as ValueObject)[key], newKey);
+      }
+    } else {
+      result[prefix] = current;
+    }
+  }
+
+  flattenHelper(obj, '');
+
+  return result;
+}
diff --git a/src/language-service/language-service.documentation.ts b/src/language-service/language-service.documentation.ts
index dc5eb3b..fd457a9 100644
--- a/src/language-service/language-service.documentation.ts
+++ b/src/language-service/language-service.documentation.ts
@@ -262,6 +262,38 @@ export const BUILTIN_FUNCTION_DOCS: Record<string, FunctionDoc> = {
     params: [
       { name: 'values', description: 'Values to check.', isVariadic: true }
     ]
+  },
+  /**
+   * Object functions
+   */
+  merge: {
+    name: 'merge',
+    description: 'Merge two or more objects together. Duplicate keys are overwritten by later arguments.',
+    params: [
+      { name: 'objects', description: 'Objects to merge.', isVariadic: true }
+    ]
+  },
+  keys: {
+    name: 'keys',
+    description: 'Return an array of strings containing the keys of the object.',
+    params: [
+      { name: 'obj', description: 'Input object.' }
+    ]
+  },
+  values: {
+    name: 'values',
+    description: 'Return an array containing the values of the object.',
+    params: [
+      { name: 'obj', description: 'Input object.' }
+    ]
+  },
+  flatten: {
+    name: 'flatten',
+    description: 'Flatten a nested object\'s keys using an optional separator (default: _). For example, {foo: {bar: 1}} becomes {foo_bar: 1}.',
+    params: [
+      { name: 'obj', description: 'Input object.' },
+      { name: 'separator', description: 'Key separator (default: _).', optional: true }
+    ]
   }
 };
 
diff --git a/src/parsing/parser.ts b/src/parsing/parser.ts
index f629af2..6007043 100644
--- a/src/parsing/parser.ts
+++ b/src/parsing/parser.ts
@@ -6,7 +6,7 @@ import { Expression } from '../core/expression.js';
 import type { Value, VariableResolveResult, Values } from '../types/values.js';
 import type { Instruction } from './instruction.js';
 import type { OperatorFunction } from '../types/parser.js';
-import { atan2, condition, fac, filter, fold, gamma, hypot, indexOf, join, map, max, min, random, roundTo, sum, json, stringLength, isEmpty, stringContains, startsWith, endsWith, searchCount, trim, toUpper, toLower, toTitle, split, repeat, reverse, left, right, replace, replaceFirst, naturalSort, toNumber, toBoolean, padLeft, padRight, padBoth, slice, urlEncode, base64Encode, base64Decode, coalesceString } from '../functions/index.js';
+import { atan2, condition, fac, filter, fold, gamma, hypot, indexOf, join, map, max, min, random, roundTo, sum, json, stringLength, isEmpty, stringContains, startsWith, endsWith, searchCount, trim, toUpper, toLower, toTitle, split, repeat, reverse, left, right, replace, replaceFirst, naturalSort, toNumber, toBoolean, padLeft, padRight, padBoth, slice, urlEncode, base64Encode, base64Decode, coalesceString, merge, keys, values, flatten } from '../functions/index.js';
 import {
   add,
   sub,
@@ -224,7 +224,12 @@ export class Parser {
       urlEncode: urlEncode,
       base64Encode: base64Encode,
       base64Decode: base64Decode,
-      coalesce: coalesceString
+      coalesce: coalesceString,
+      // Object manipulation functions
+      merge: merge,
+      keys: keys,
+      values: values,
+      flatten: flatten
     };
 
     this.numericConstants = {
diff --git a/test/functions/functions-object.ts b/test/functions/functions-object.ts
new file mode 100644
index 0000000..4681da3
--- /dev/null
+++ b/test/functions/functions-object.ts
@@ -0,0 +1,166 @@
+/* global describe, it */
+
+import assert from 'assert';
+import { Parser } from '../../index';
+
+describe('Object Functions TypeScript Test', function () {
+  describe('merge(obj1, obj2, ...)', function () {
+    it('should return empty object when called with no arguments', function () {
+      const parser = new Parser();
+      assert.deepStrictEqual(parser.evaluate('merge()'), {});
+    });
+
+    it('should return the object when called with one argument', function () {
+      const parser = new Parser();
+      assert.deepStrictEqual(parser.evaluate('merge({a: 1})'), { a: 1 });
+    });
+
+    it('should merge two objects', function () {
+      const parser = new Parser();
+      assert.deepStrictEqual(parser.evaluate('merge({a: 1}, {b: 2})'), { a: 1, b: 2 });
+    });
+
+    it('should override duplicate keys with later arguments', function () {
+      const parser = new Parser();
+      assert.deepStrictEqual(parser.evaluate('merge({a: 1, b: 2}, {b: 3, c: 4})'), { a: 1, b: 3, c: 4 });
+    });
+
+    it('should merge three or more objects', function () {
+      const parser = new Parser();
+      assert.deepStrictEqual(
+        parser.evaluate('merge({a: 1}, {b: 2}, {c: 3})'),
+        { a: 1, b: 2, c: 3 }
+      );
+    });
+
+    it('should return undefined if any argument is undefined', function () {
+      const parser = new Parser();
+      assert.strictEqual(parser.evaluate('merge({a: 1}, undefined)'), undefined);
+      assert.strictEqual(parser.evaluate('merge(undefined, {a: 1})'), undefined);
+    });
+
+    it('should work with variables', function () {
+      const parser = new Parser();
+      assert.deepStrictEqual(
+        parser.evaluate('merge(obj1, obj2)', { obj1: { x: 10 }, obj2: { y: 20 } }),
+        { x: 10, y: 20 }
+      );
+    });
+  });
+
+  describe('keys(obj)', function () {
+    it('should return empty array for empty object', function () {
+      const parser = new Parser();
+      assert.deepStrictEqual(parser.evaluate('keys({})'), []);
+    });
+
+    it('should return keys of an object', function () {
+      const parser = new Parser();
+      const result = parser.evaluate('keys({a: 1, b: 2, c: 3})') as string[];
+      assert.strictEqual(result.length, 3);
+      assert(result.includes('a'));
+      assert(result.includes('b'));
+      assert(result.includes('c'));
+    });
+
+    it('should return undefined if argument is undefined', function () {
+      const parser = new Parser();
+      assert.strictEqual(parser.evaluate('keys(undefined)'), undefined);
+    });
+
+    it('should work with variables', function () {
+      const parser = new Parser();
+      const result = parser.evaluate('keys(obj)', { obj: { foo: 'bar', baz: 42 } }) as string[];
+      assert.strictEqual(result.length, 2);
+      assert(result.includes('foo'));
+      assert(result.includes('baz'));
+    });
+  });
+
+  describe('values(obj)', function () {
+    it('should return empty array for empty object', function () {
+      const parser = new Parser();
+      assert.deepStrictEqual(parser.evaluate('values({})'), []);
+    });
+
+    it('should return values of an object', function () {
+      const parser = new Parser();
+      const result = parser.evaluate('values({a: 1, b: 2, c: 3})') as number[];
+      assert.strictEqual(result.length, 3);
+      assert(result.includes(1));
+      assert(result.includes(2));
+      assert(result.includes(3));
+    });
+
+    it('should return undefined if argument is undefined', function () {
+      const parser = new Parser();
+      assert.strictEqual(parser.evaluate('values(undefined)'), undefined);
+    });
+
+    it('should work with variables', function () {
+      const parser = new Parser();
+      const result = parser.evaluate('values(obj)', { obj: { foo: 'bar', baz: 42 } });
+      assert(Array.isArray(result));
+      assert.strictEqual((result as any[]).length, 2);
+      assert((result as any[]).includes('bar'));
+      assert((result as any[]).includes(42));
+    });
+  });
+
+  describe('flatten(obj)', function () {
+    it('should return empty object for empty object', function () {
+      const parser = new Parser();
+      assert.deepStrictEqual(parser.evaluate('flatten({})'), {});
+    });
+
+    it('should return same object for flat object', function () {
+      const parser = new Parser();
+      assert.deepStrictEqual(parser.evaluate('flatten({a: 1, b: 2})'), { a: 1, b: 2 });
+    });
+
+    it('should flatten nested object', function () {
+      const parser = new Parser();
+      assert.deepStrictEqual(
+        parser.evaluate('flatten(obj)', { obj: { foo: { bar: 1 } } }),
+        { foo_bar: 1 }
+      );
+    });
+
+    it('should flatten deeply nested object', function () {
+      const parser = new Parser();
+      assert.deepStrictEqual(
+        parser.evaluate('flatten(obj)', { obj: { a: { b: { c: 1 } } } }),
+        { a_b_c: 1 }
+      );
+    });
+
+    it('should handle mixed nested and flat keys', function () {
+      const parser = new Parser();
+      assert.deepStrictEqual(
+        parser.evaluate('flatten(obj)', { obj: { a: 1, b: { c: 2, d: 3 }, e: 4 } }),
+        { a: 1, b_c: 2, b_d: 3, e: 4 }
+      );
+    });
+
+    it('should preserve arrays as values', function () {
+      const parser = new Parser();
+      assert.deepStrictEqual(
+        parser.evaluate('flatten(obj)', { obj: { a: { b: [1, 2, 3] } } }),
+        { a_b: [1, 2, 3] }
+      );
+    });
+
+    it('should return undefined if argument is undefined', function () {
+      const parser = new Parser();
+      assert.strictEqual(parser.evaluate('flatten(undefined)'), undefined);
+    });
+
+    it('should use custom separator when provided', function () {
+      const parser = new Parser();
+      assert.deepStrictEqual(
+        parser.evaluate('flatten(obj, ".")', { obj: { foo: { bar: 1 } } }),
+        { 'foo.bar': 1 }
+      );
+    });
+  });
+});