diff --git a/src/storm-gspn/parser/GspnParser.h b/src/storm-gspn/parser/GspnParser.h
index 512f0ddd6..b27c8975a 100644
--- a/src/storm-gspn/parser/GspnParser.h
+++ b/src/storm-gspn/parser/GspnParser.h
@@ -1,3 +1,5 @@
+#pragma once
+
 #include "storm-gspn/storage/gspn/GSPN.h"
 
 namespace storm {