diff --git a/Tools/AP_Periph/AP_Periph.h b/Tools/AP_Periph/AP_Periph.h
index 97c89cdd3b..a025883ad7 100644
--- a/Tools/AP_Periph/AP_Periph.h
+++ b/Tools/AP_Periph/AP_Periph.h
@@ -37,6 +37,9 @@
 #include "batt_balance.h"
 #include "networking.h"
 #include "serial_options.h"
+#if AP_SIM_ENABLED
+#include <SITL/SITL.h>
+#endif
 
 #include <AP_NMEA_Output/AP_NMEA_Output.h>
 #if HAL_NMEA_OUTPUT_ENABLED && !(HAL_GCS_ENABLED && defined(HAL_PERIPH_ENABLE_GPS))
diff --git a/Tools/AP_Periph/hwing_esc.cpp b/Tools/AP_Periph/hwing_esc.cpp
index 871c2e0517..a1e2d4a472 100644
--- a/Tools/AP_Periph/hwing_esc.cpp
+++ b/Tools/AP_Periph/hwing_esc.cpp
@@ -14,6 +14,8 @@
 
 #ifdef HAL_PERIPH_ENABLE_HWESC
 
+#include <SITL/SITL.h>
+
 extern const AP_HAL::HAL& hal;
 
 #define TELEM_HEADER 0x9B