diff --git a/libraries/AP_HAL_AVR_SITL/UARTDriver.cpp b/libraries/AP_HAL_AVR_SITL/UARTDriver.cpp
index d32213c4e5..5663b4c4fa 100644
--- a/libraries/AP_HAL_AVR_SITL/UARTDriver.cpp
+++ b/libraries/AP_HAL_AVR_SITL/UARTDriver.cpp
@@ -34,6 +34,7 @@
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
+#include <sys/select.h>
 
 #include "UARTDriver.h"
 #include "SITL_State.h"