diff --git a/platform/x11/godot_x11.cpp b/platform/x11/godot_x11.cpp
index b727ecbd170..adb919c2f16 100644
--- a/platform/x11/godot_x11.cpp
+++ b/platform/x11/godot_x11.cpp
@@ -28,6 +28,7 @@
 /*************************************************************************/
 #include <unistd.h>
 #include <limits.h>
+#include <stdlib.h>
 
 #include "main/main.h"
 #include "os_x11.h"