diff --git a/src/wp-includes/rest-api.php b/src/wp-includes/rest-api.php
index ffc691916f..3d0b7ee6d5 100644
--- a/src/wp-includes/rest-api.php
+++ b/src/wp-includes/rest-api.php
@@ -256,7 +256,7 @@ function rest_api_loaded() {
 	$server = rest_get_server();
 
 	// Fire off the request.
-	$server->serve_request( $GLOBALS['wp']->query_vars['rest_route'] );
+	$server->serve_request( untrailingslashit( $GLOBALS['wp']->query_vars['rest_route'] ) );
 
 	// We're done.
 	die();