diff --git a/src/basic/namespace-util.h b/src/basic/namespace-util.h
index e0e857b7a4..e15afd9340 100644
--- a/src/basic/namespace-util.h
+++ b/src/basic/namespace-util.h
@@ -1,6 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
+#include <sched.h>              /* IWYU pragma: export */
+
 #include "forward.h"
 
 typedef enum NamespaceType {