diff --git a/src/osx/carbon/utilscocoa.mm b/src/osx/carbon/utilscocoa.mm
index 67c2f6ed3b..9b70c90360 100644
--- a/src/osx/carbon/utilscocoa.mm
+++ b/src/osx/carbon/utilscocoa.mm
@@ -555,6 +555,8 @@ wxOSXEffectiveAppearanceSetter::wxOSXEffectiveAppearanceSetter()
         formerAppearance = NSAppearance.currentAppearance;
         NSAppearance.currentAppearance = NSApp.effectiveAppearance;
     }
+#else
+    wxUnusedVar(formerAppearance);
 #endif
 }