diff --git a/Tools/Replay/Replay.pde b/Tools/Replay/Replay.pde
index bd75b1ec9b..70c6c3f587 100644
--- a/Tools/Replay/Replay.pde
+++ b/Tools/Replay/Replay.pde
@@ -48,6 +48,7 @@
 #include <AP_Rally.h>
 #include <AP_BattMonitor.h>
 #include <AP_Terrain.h>
+#include <AP_OpticalFlow.h>
 #include <Parameters.h>
 #include <stdio.h>
 #include <getopt.h>