diff --git a/src/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php b/src/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
index 589e0e2ccec17..9e95a807f1511 100644
--- a/src/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
+++ b/src/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
@@ -82,17 +82,31 @@ protected function prepare_items_query( $prepared_args = array(), $request = nul
 			$query_args['post_status'] = 'inherit';
 		}
 
-		$media_types = $this->get_media_types();
+		$all_mime_types = array();
+		$media_types    = $this->get_media_types();
 
-		if ( ! empty( $request['media_type'] ) && isset( $media_types[ $request['media_type'] ] ) ) {
-			$query_args['post_mime_type'] = $media_types[ $request['media_type'] ];
+		if ( ! empty( $request['media_type'] ) ) {
+			$media_type_input = is_array( $request['media_type'] )
+				? $request['media_type']
+				: explode( ',', $request['media_type'] );
+
+			foreach ( array_map( 'trim', $media_type_input ) as $type ) {
+				if ( isset( $media_types[ $type ] ) ) {
+					$all_mime_types = array_merge( $all_mime_types, $media_types[ $type ] );
+				}
+			}
 		}
 
 		if ( ! empty( $request['mime_type'] ) ) {
-			$parts = explode( '/', $request['mime_type'] );
-			if ( isset( $media_types[ $parts[0] ] ) && in_array( $request['mime_type'], $media_types[ $parts[0] ], true ) ) {
-				$query_args['post_mime_type'] = $request['mime_type'];
-			}
+			$mime_type_input = is_array( $request['mime_type'] )
+				? $request['mime_type']
+				: explode( ',', $request['mime_type'] );
+
+			$all_mime_types = array_merge( $all_mime_types, array_map( 'trim', $mime_type_input ) );
+		}
+
+		if ( ! empty( $all_mime_types ) ) {
+			$query_args['post_mime_type'] = array_values( array_unique( $all_mime_types ) );
 		}
 
 		// Filter query clauses to include filenames.
@@ -1285,19 +1299,24 @@ public function get_collection_params() {
 		$params                            = parent::get_collection_params();
 		$params['status']['default']       = 'inherit';
 		$params['status']['items']['enum'] = array( 'inherit', 'private', 'trash' );
-		$media_types                       = $this->get_media_types();
 
 		$params['media_type'] = array(
 			'default'     => null,
-			'description' => __( 'Limit result set to attachments of a particular media type.' ),
-			'type'        => 'string',
-			'enum'        => array_keys( $media_types ),
+			'description' => __( 'Limit result set to attachments of particular media types.' ),
+			'type'        => array( 'string', 'array' ),
+			'items'       => array(
+				'type' => 'string',
+				'enum' => array_keys( $this->get_media_types() ),
+			),
 		);
 
 		$params['mime_type'] = array(
 			'default'     => null,
-			'description' => __( 'Limit result set to attachments of a particular MIME type.' ),
-			'type'        => 'string',
+			'description' => __( 'Limit result set to attachments of particular MIME types.' ),
+			'type'        => array( 'string', 'array' ),
+			'items'       => array(
+				'type' => 'string',
+			),
 		);
 
 		return $params;
diff --git a/tests/phpunit/tests/rest-api/rest-attachments-controller.php b/tests/phpunit/tests/rest-api/rest-attachments-controller.php
index d065238b8beb7..df0bd04e630ce 100644
--- a/tests/phpunit/tests/rest-api/rest-attachments-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-attachments-controller.php
@@ -267,7 +267,7 @@ public function test_registered_query_params() {
 			'audio',
 			'text',
 		);
-		$this->assertSameSets( $media_types, $data['endpoints'][0]['args']['media_type']['enum'] );
+		$this->assertSameSets( $media_types, $data['endpoints'][0]['args']['media_type']['items']['enum'] );
 	}
 
 	public function test_registered_get_item_params() {
@@ -441,6 +441,153 @@ public function test_get_items_mime_type() {
 		$this->assertSame( $id1, $data[0]['id'] );
 	}
 
+	/**
+	 * Test multiple media types support with various input formats.
+	 *
+	 * @ticket 63668
+	 */
+	public function test_get_items_multiple_media_types() {
+		$image_id = self::factory()->attachment->create_object(
+			self::$test_file,
+			0,
+			array(
+				'post_mime_type' => 'image/jpeg',
+			)
+		);
+
+		$video_id = self::factory()->attachment->create_object(
+			self::$test_file,
+			0,
+			array(
+				'post_mime_type' => 'video/mp4',
+			)
+		);
+
+		$audio_id = self::factory()->attachment->create_object(
+			self::$test_file,
+			0,
+			array(
+				'post_mime_type' => 'audio/mpeg',
+			)
+		);
+
+		$request = new WP_REST_Request( 'GET', '/wp/v2/media' );
+
+		// Test single media type
+		$request->set_param( 'media_type', 'image' );
+		$response = rest_get_server()->dispatch( $request );
+		$data     = $response->get_data();
+		$this->assertCount( 1, $data );
+		$this->assertSame( $image_id, $data[0]['id'] );
+
+		// Test multiple media types with comma-separated string
+		$request->set_param( 'media_type', 'image,video' );
+		$response = rest_get_server()->dispatch( $request );
+		$data     = $response->get_data();
+		$this->assertCount( 2, $data );
+		$ids = wp_list_pluck( $data, 'id' );
+		$this->assertContains( $image_id, $ids );
+		$this->assertContains( $video_id, $ids );
+		$this->assertNotContains( $audio_id, $ids );
+
+		// Test multiple media types with array format
+		$request->set_param( 'media_type', array( 'image', 'video', 'audio' ) );
+		$response = rest_get_server()->dispatch( $request );
+		$data     = $response->get_data();
+		$this->assertCount( 3, $data );
+		$ids = wp_list_pluck( $data, 'id' );
+		$this->assertContains( $image_id, $ids );
+		$this->assertContains( $video_id, $ids );
+		$this->assertContains( $audio_id, $ids );
+
+		// Test invalid media type mixed with valid ones
+		$request->set_param( 'media_type', 'image,invalid,video' );
+		$response = rest_get_server()->dispatch( $request );
+		$data     = $response->get_data();
+		$this->assertCount( 2, $data );
+		$ids = wp_list_pluck( $data, 'id' );
+		$this->assertContains( $image_id, $ids );
+		$this->assertContains( $video_id, $ids );
+	}
+
+	/**
+	 * Test multiple MIME types support and combination with media types.
+	 *
+	 * @ticket 63668
+	 */
+	public function test_get_items_multiple_mime_types_and_combination() {
+		$jpeg_id = self::factory()->attachment->create_object(
+			self::$test_file,
+			0,
+			array(
+				'post_mime_type' => 'image/jpeg',
+			)
+		);
+
+		$png_id = self::factory()->attachment->create_object(
+			self::$test_file2,
+			0,
+			array(
+				'post_mime_type' => 'image/png',
+			)
+		);
+
+		$mp4_id = self::factory()->attachment->create_object(
+			self::$test_file,
+			0,
+			array(
+				'post_mime_type' => 'video/mp4',
+			)
+		);
+
+		$pdf_id = self::factory()->attachment->create_object(
+			self::$test_file,
+			0,
+			array(
+				'post_mime_type' => 'application/pdf',
+			)
+		);
+
+		$request = new WP_REST_Request( 'GET', '/wp/v2/media' );
+
+		// Test single MIME type
+		$request->set_param( 'mime_type', 'image/jpeg' );
+		$response = rest_get_server()->dispatch( $request );
+		$data     = $response->get_data();
+		$this->assertCount( 1, $data );
+		$this->assertSame( $jpeg_id, $data[0]['id'] );
+
+		// Test multiple MIME types with comma-separated string
+		$request->set_param( 'mime_type', 'image/jpeg,image/png' );
+		$response = rest_get_server()->dispatch( $request );
+		$data     = $response->get_data();
+		$this->assertCount( 2, $data );
+		$ids = wp_list_pluck( $data, 'id' );
+		$this->assertContains( $jpeg_id, $ids );
+		$this->assertContains( $png_id, $ids );
+
+		// Test multiple MIME types with array format
+		$request->set_param( 'mime_type', array( 'image/jpeg', 'video/mp4' ) );
+		$response = rest_get_server()->dispatch( $request );
+		$data     = $response->get_data();
+		$this->assertCount( 2, $data );
+		$ids = wp_list_pluck( $data, 'id' );
+		$this->assertContains( $jpeg_id, $ids );
+		$this->assertContains( $mp4_id, $ids );
+
+		// Test multiple media types with multiple MIME types
+		$request->set_param( 'media_type', 'image,video' );
+		$request->set_param( 'mime_type', 'application/pdf' );
+		$response = rest_get_server()->dispatch( $request );
+		$data     = $response->get_data();
+		$this->assertCount( 4, $data );
+		$ids = wp_list_pluck( $data, 'id' );
+		$this->assertContains( $jpeg_id, $ids );
+		$this->assertContains( $png_id, $ids );
+		$this->assertContains( $mp4_id, $ids );
+		$this->assertContains( $pdf_id, $ids );
+	}
+
 	public function test_get_items_parent() {
 		$post_id        = self::factory()->post->create( array( 'post_title' => 'Test Post' ) );
 		$attachment_id  = self::factory()->attachment->create_object(