diff --git a/src/wp-includes/post.php b/src/wp-includes/post.php
index 3bfede95da..97a3fb8f77 100644
--- a/src/wp-includes/post.php
+++ b/src/wp-includes/post.php
@@ -7489,6 +7489,22 @@ function update_post_author_caches( $posts ) {
 	cache_users( $author_ids );
 }
 
+/**
+ * Prime post parent post caches.
+ *
+ * @since 6.1.0
+ *
+ * @param WP_Post[] $posts Array of Post objects.
+ */
+function update_post_parent_caches( $posts ) {
+	$parent_ids = wp_list_pluck( $posts, 'post_parent' );
+	$parent_ids = array_map( 'absint', $parent_ids );
+	$parent_ids = array_unique( array_filter( $parent_ids ) );
+	if ( ! empty( $parent_ids ) ) {
+		_prime_post_caches( $parent_ids, false );
+	}
+}
+
 /**
  * Updates metadata cache for a list of post IDs.
  *
diff --git a/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php b/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
index ae203b41aa..87de7a2421 100644
--- a/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
+++ b/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
@@ -369,6 +369,7 @@ class WP_REST_Posts_Controller extends WP_REST_Controller {
 
 		$posts = array();
 
+		update_post_parent_caches( $query_result );
 		update_post_author_caches( $query_result );
 		if ( post_type_supports( $this->post_type, 'thumbnail' ) ) {
 			update_post_thumbnail_cache( $posts_query );
diff --git a/tests/phpunit/tests/rest-api/rest-posts-controller.php b/tests/phpunit/tests/rest-api/rest-posts-controller.php
index e4d7b5de4b..54d1cc0167 100644
--- a/tests/phpunit/tests/rest-api/rest-posts-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-posts-controller.php
@@ -1787,6 +1787,47 @@ class WP_Test_REST_Posts_Controller extends WP_Test_REST_Post_Type_Controller_Te
 		$this->assertSame( $formats, $data['schema']['properties']['format']['enum'] );
 	}
 
+	/**
+	 * @ticket 55593
+	 */
+	public function test_get_items_parent_ids_primed() {
+		$parent_id1 = self::$post_ids[0];
+		$parent_id2 = self::$post_ids[1];
+		$parent_ids = array( $parent_id2, $parent_id1 );
+
+		$this->factory->attachment->create_object(
+			DIR_TESTDATA . '/images/canola.jpg',
+			$parent_id1,
+			array(
+				'post_mime_type' => 'image/jpeg',
+				'post_excerpt'   => 'A sample caption 1',
+			)
+		);
+
+		$this->factory->attachment->create_object(
+			DIR_TESTDATA . '/images/canola.jpg',
+			$parent_id2,
+			array(
+				'post_mime_type' => 'image/jpeg',
+				'post_excerpt'   => 'A sample caption 2',
+			)
+		);
+
+		// Attachment creation warms parent ids. Needs clean up for test.
+		wp_cache_delete_multiple( $parent_ids, 'posts' );
+
+		$filter = new MockAction();
+		add_filter( 'update_post_metadata_cache', array( $filter, 'filter' ), 10, 2 );
+
+		$request = new WP_REST_Request( 'GET', '/wp/v2/media' );
+		rest_get_server()->dispatch( $request );
+
+		$args = $filter->get_args();
+		$last = end( $args );
+		$this->assertIsArray( $last, 'The last value is not an array' );
+		$this->assertEqualSets( $parent_ids, $last[1] );
+	}
+
 	public function test_get_item() {
 		$request  = new WP_REST_Request( 'GET', sprintf( '/wp/v2/posts/%d', self::$post_id ) );
 		$response = rest_get_server()->dispatch( $request );