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 e0cdc79a2f..872a6607cb 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
@@ -148,6 +148,11 @@ class WP_REST_Posts_Controller extends WP_REST_Controller {
 			return new WP_Error( 'rest_no_search_term_defined', __( 'You need to define a search term to order by relevance.' ), array( 'status' => 400 ) );
 		}
 
+		// Ensure an include parameter is set in case the orderby is set to 'include'.
+		if ( ! empty( $request['orderby'] ) && 'include' === $request['orderby'] && empty( $request['include'] ) ) {
+			return new WP_Error( 'rest_orderby_include_missing_include', sprintf( __( 'Missing parameter(s): %s' ), 'include' ), array( 'status' => 400 ) );
+		}
+
 		// Retrieve the list of registered collection query parameters.
 		$registered = $this->get_collection_params();
 		$args = array();
@@ -836,8 +841,17 @@ class WP_REST_Posts_Controller extends WP_REST_Controller {
 			$query_args['ignore_sticky_posts'] = true;
 		}
 
-		if ( 'include' === $query_args['orderby'] ) {
-			$query_args['orderby'] = 'post__in';
+		// Map to proper WP_Query orderby param.
+		if ( isset( $query_args['orderby'] ) && isset( $request['orderby'] ) ) {
+			$orderby_mappings = array(
+				'id'      => 'ID',
+				'include' => 'post__in',
+				'slug'    => 'post_name',
+			);
+
+			if ( isset( $orderby_mappings[ $request['orderby'] ] ) ) {
+				$query_args['orderby'] = $orderby_mappings[ $request['orderby'] ];
+			}
 		}
 
 		return $query_args;
diff --git a/tests/phpunit/tests/rest-api/rest-posts-controller.php b/tests/phpunit/tests/rest-api/rest-posts-controller.php
index 8f8bc73476..886ae3c5a6 100644
--- a/tests/phpunit/tests/rest-api/rest-posts-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-posts-controller.php
@@ -444,6 +444,50 @@ class WP_Test_REST_Posts_Controller extends WP_Test_REST_Post_Type_Controller_Te
 		$this->assertErrorResponse( 'rest_invalid_param', $response, 400 );
 	}
 
+	public function test_get_items_with_orderby_include_without_include_param() {
+		$this->factory->post->create( array( 'post_status' => 'publish' ) );
+		$request = new WP_REST_Request( 'GET', '/wp/v2/posts' );
+		$request->set_param( 'orderby', 'include' );
+
+		$response = $this->server->dispatch( $request );
+
+		$this->assertErrorResponse( 'rest_orderby_include_missing_include', $response, 400 );
+	}
+
+	public function test_get_items_with_orderby_id() {
+		$id1 = $this->factory->post->create( array( 'post_status' => 'publish', 'post_date' => '2016-01-13 02:26:48' ) );
+		$id2 = $this->factory->post->create( array( 'post_status' => 'publish', 'post_date' => '2016-01-12 02:26:48' ) );
+		$id3 = $this->factory->post->create( array( 'post_status' => 'publish', 'post_date' => '2016-01-11 02:26:48' ) );
+
+		$request = new WP_REST_Request( 'GET', '/wp/v2/posts' );
+		$request->set_param( 'orderby', 'id' );
+		$request->set_param( 'include', array( $id1, $id2, $id3 ) );
+
+		$response = $this->server->dispatch( $request );
+		$data = $response->get_data();
+
+		// Default ORDER is DESC.
+		$this->assertEquals( $id3, $data[0]['id'] );
+		$this->assertEquals( $id2, $data[1]['id'] );
+		$this->assertEquals( $id1, $data[2]['id'] );
+	}
+
+	public function test_get_items_with_orderby_slug() {
+		$id1 = $this->factory->post->create( array( 'post_title' => 'ABC', 'post_name' => 'xyz', 'post_status' => 'publish' ) );
+		$id2 = $this->factory->post->create( array( 'post_title' => 'XYZ', 'post_name' => 'abc', 'post_status' => 'publish' ) );
+
+		$request = new WP_REST_Request( 'GET', '/wp/v2/posts' );
+		$request->set_param( 'orderby', 'slug' );
+		$request->set_param( 'include', array( $id1, $id2 ) );
+
+		$response = $this->server->dispatch( $request );
+		$data = $response->get_data();
+
+		// Default ORDER is DESC.
+		$this->assertEquals( 'xyz', $data[0]['slug'] );
+		$this->assertEquals( 'abc', $data[1]['slug'] );
+	}
+
 	public function test_get_items_with_orderby_relevance() {
 		$this->factory->post->create( array( 'post_title' => 'Title is more relevant', 'post_content' => 'Content is', 'post_status' => 'publish' ) );
 		$this->factory->post->create( array( 'post_title' => 'Title is', 'post_content' => 'Content is less relevant', 'post_status' => 'publish' ) );