diff --git a/tools/viewer/Viewer.h b/tools/viewer/Viewer.h
index f121c17..24f68b4 100644
--- a/tools/viewer/Viewer.h
+++ b/tools/viewer/Viewer.h
@@ -13,6 +13,7 @@
 #include "sk_app/Window.h"
 #include "gm.h"
 #include "SkAnimTimer.h"
+#include "SkJSONCPP.h"
 #include "SkTouchGesture.h"
 #include "Slide.h"