diff --git a/libraries/AP_GPS/AP_GPS_SITL.cpp b/libraries/AP_GPS/AP_GPS_SITL.cpp
index e671ce05f5..c423983adf 100644
--- a/libraries/AP_GPS/AP_GPS_SITL.cpp
+++ b/libraries/AP_GPS/AP_GPS_SITL.cpp
@@ -21,6 +21,7 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <sys/time.h>
 
 extern const AP_HAL::HAL& hal;