diff --git a/lib/compat/wordpress-6.5/fonts/class-wp-font-library.php b/lib/compat/wordpress-6.5/fonts/class-wp-font-library.php
index 0921d29c7b1c43..141dff730a15fc 100644
--- a/lib/compat/wordpress-6.5/fonts/class-wp-font-library.php
+++ b/lib/compat/wordpress-6.5/fonts/class-wp-font-library.php
@@ -117,14 +117,13 @@ public function get_font_collections() {
 		 * @since 6.5.0
 		 *
 		 * @param string $slug Font collection slug.
-		 * @return WP_Font_Collection|WP_Error Font collection object,
-		 *                                     or WP_Error object if the font collection doesn't exist.
+		 * @return WP_Font_Collection|null Font collection object, or null if the font collection doesn't exist.
 		 */
 		public function get_font_collection( $slug ) {
 			if ( $this->is_collection_registered( $slug ) ) {
 				return $this->collections[ $slug ];
 			}
-			return new WP_Error( 'font_collection_not_found', __( 'Font collection not found.', 'gutenberg' ) );
+			return null;
 		}
 
 		/**
diff --git a/lib/compat/wordpress-6.5/fonts/class-wp-rest-font-collections-controller.php b/lib/compat/wordpress-6.5/fonts/class-wp-rest-font-collections-controller.php
index 90ee80649bb489..10f77ddc4b3a46 100644
--- a/lib/compat/wordpress-6.5/fonts/class-wp-rest-font-collections-controller.php
+++ b/lib/compat/wordpress-6.5/fonts/class-wp-rest-font-collections-controller.php
@@ -144,10 +144,9 @@ public function get_item( $request ) {
 			$slug       = $request->get_param( 'slug' );
 			$collection = WP_Font_Library::get_instance()->get_font_collection( $slug );
 
-			// If the collection doesn't exist returns a 404.
-			if ( is_wp_error( $collection ) ) {
-				$collection->add_data( array( 'status' => 404 ) );
-				return $collection;
+			// @TODO: remove `is_wp_error` check once WP trunk is updated to return null when a collection is not found.
+			if ( ! $collection || is_wp_error( $collection ) ) {
+				return new WP_Error( 'rest_font_collection_not_found', __( 'Font collection not found.' ), array( 'status' => 404 ) );
 			}
 
 			return $this->prepare_item_for_response( $collection, $request );
diff --git a/phpunit/tests/fonts/font-library/wpRestFontCollectionsController.php b/phpunit/tests/fonts/font-library/wpRestFontCollectionsController.php
index df2daccb5d24f0..0f7fe8f9c662bb 100644
--- a/phpunit/tests/fonts/font-library/wpRestFontCollectionsController.php
+++ b/phpunit/tests/fonts/font-library/wpRestFontCollectionsController.php
@@ -121,7 +121,7 @@ public function test_get_item_invalid_slug() {
 		wp_set_current_user( self::$admin_id );
 		$request  = new WP_REST_Request( 'GET', '/wp/v2/font-collections/non-existing-collection' );
 		$response = rest_get_server()->dispatch( $request );
-		$this->assertErrorResponse( 'font_collection_not_found', $response, 404 );
+		$this->assertErrorResponse( 'rest_font_collection_not_found', $response, 404 );
 	}
 
 	/**