diff --git a/mrv2/lib/mrvFl/mrvCallbacks.cpp b/mrv2/lib/mrvFl/mrvCallbacks.cpp
index 0e4aa6103..3beed1085 100644
--- a/mrv2/lib/mrvFl/mrvCallbacks.cpp
+++ b/mrv2/lib/mrvFl/mrvCallbacks.cpp
@@ -33,7 +33,7 @@ namespace fs = std::filesystem;
 #include "mrvHotkeyUI.h"
 #include "mrViewer.h"
 
-#include <FL/FL.H>
+#include <FL/Fl.H>
 
 #include "mrvFl/mrvIO.h"