diff --git a/cockatrice/src/game/zones/select_zone.h b/cockatrice/src/game/zones/select_zone.h
index 4ee6d3b1b..07a8d7a0d 100644
--- a/cockatrice/src/game/zones/select_zone.h
+++ b/cockatrice/src/game/zones/select_zone.h
@@ -3,6 +3,8 @@
 
 #include "card_zone.h"
 
+#include <QSet>
+
 /**
  * A CardZone where the cards are laid out, with each card directly interactable by clicking.
  */