diff --git a/cairomm/surface.h b/cairomm/surface.h
index c923e6086..8cfaa76a3 100644
--- a/cairomm/surface.h
+++ b/cairomm/surface.h
@@ -49,6 +49,7 @@
 #include <cairo-glitz.h>
 #endif // CAIRO_HAS_GLITZ_SURFACE
 
+#undef WIN32
 
 namespace Cairo
 {