diff --git a/stl/inc/mdspan b/stl/inc/mdspan
index c79cfa17836..e06ca1a4d2b 100644
--- a/stl/inc/mdspan
+++ b/stl/inc/mdspan
@@ -3,7 +3,6 @@
 // Copyright (c) Microsoft Corporation.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-#pragma once
 #ifndef _MDSPAN_
 #define _MDSPAN_
 #include <yvals.h>