diff --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap
--- a/libcxx/include/module.modulemap
+++ b/libcxx/include/module.modulemap
@@ -51,6 +51,7 @@
       export *
     }
     module stdatomic_h {
+      requires cplusplus23
       header "stdatomic.h"
       export *
     }