diff --git a/lib/HALSim/Keyboard.h b/lib/HALSim/Keyboard.h
index 1f7af3c8..77dbb5ac 100644
--- a/lib/HALSim/Keyboard.h
+++ b/lib/HALSim/Keyboard.h
@@ -43,6 +43,7 @@
 /******************************************************************************
  * Includes
  *****************************************************************************/
+#include <stdint.h>
 #include <webots/Keyboard.hpp>
 #include <webots/Robot.hpp>