diff --git a/epan/dissectors/Makefile.nmake b/epan/dissectors/Makefile.nmake
index 02928d6380..4fc827e860 100644
--- a/epan/dissectors/Makefile.nmake
+++ b/epan/dissectors/Makefile.nmake
@@ -76,7 +76,7 @@ x11-declarations.h x11-register-info.h: x11-fields process-x11-fields.pl
 register.c: $(DISSECTOR_SRC)
 !IFDEF PYTHON
 	@echo Making register.c (using python)
-	@$(PYTHON) ../../tools/make-dissector-reg.py . dissectors $(DISSECTOR_SRC)
+	@$(PYTHON) "../../tools/make-dissector-reg.py" . dissectors $(DISSECTOR_SRC)
 !ELSE
 	@echo Making register.c (using sh)
 	@$(SH) ../../tools/make-dissector-reg . dissectors $(DISSECTOR_SRC)