diff --git a/FL/Fl_Printer.H b/FL/Fl_Printer.H
index 435834f40..877251e6e 100644
--- a/FL/Fl_Printer.H
+++ b/FL/Fl_Printer.H
@@ -41,7 +41,7 @@
 #if !(defined(__APPLE__) || defined(WIN32))
 #include <FL/Fl_PostScript.H>
 #elif defined(WIN32)
-#include <Commdlg.h>
+#include <commdlg.h>
 #endif
 
 #if defined(__APPLE__) || defined(WIN32) || defined(FL_DOXYGEN)