diff --git a/src/plugins/platforms/xcb/qxcbconnection.h b/src/plugins/platforms/xcb/qxcbconnection.h
index 4ed07fb488..cb97a0be18 100644
--- a/src/plugins/platforms/xcb/qxcbconnection.h
+++ b/src/plugins/platforms/xcb/qxcbconnection.h
@@ -56,6 +56,7 @@
 #include <QtCore/QLoggingCategory>
 #include <QtCore/private/qglobal_p.h>
 
+#include <cstdlib>
 #include <memory>
 
 // This is needed to make Qt compile together with XKB. xkb.h is using a variable