diff --git a/system_state.h b/system_state.h
index 20e11a7..cb33ce0 100644
--- a/system_state.h
+++ b/system_state.h
@@ -9,6 +9,8 @@
 #include <policy/device_policy.h>
 #include <policy/libpolicy.h>
 
+#include "update_engine/gpio_handler.h"
+
 namespace chromeos_update_engine {
 
 // SystemState is the root class within the update engine. So we should avoid