diff --git a/drivers/include/drivers/interfaces/InterfaceDigitalIn.h b/drivers/include/drivers/interfaces/InterfaceDigitalIn.h
index a8eda9e72fe..388ed8dc57d 100644
--- a/drivers/include/drivers/interfaces/InterfaceDigitalIn.h
+++ b/drivers/include/drivers/interfaces/InterfaceDigitalIn.h
@@ -20,6 +20,7 @@
 #ifndef MBED_INTERFACE_DIGITALIN_H_
 #define MBED_INTERFACE_DIGITALIN_H_
 
+#include "PinNames.h"
 
 namespace mbed {