diff --git a/source/games/duke/src/conlabel.h b/source/games/duke/src/conlabel.h
index 8dac9ea85..d8d538a0a 100644
--- a/source/games/duke/src/conlabel.h
+++ b/source/games/duke/src/conlabel.h
@@ -1,3 +1,5 @@
+#pragma once
+
 enum
 {
 	PLAYER_ZOOM = 1,