diff --git a/libraries/AP_AHRS/AP_AHRS.h b/libraries/AP_AHRS/AP_AHRS.h
index ddcb50e675..2413d60599 100644
--- a/libraries/AP_AHRS/AP_AHRS.h
+++ b/libraries/AP_AHRS/AP_AHRS.h
@@ -29,7 +29,6 @@
 #include <AP_InertialSensor/AP_InertialSensor.h>
 #include <AP_Baro/AP_Baro.h>
 #include <AP_Param/AP_Param.h>
-#include <AP_Common/Semaphore.h>
 #include <AP_Common/Location.h>
 
 class OpticalFlow;