diff --git a/lodash.js b/lodash.js
index 4ef11e86b..9dad6d52d 100644
--- a/lodash.js
+++ b/lodash.js
@@ -3423,7 +3423,7 @@
         includes = arrayIncludesWith;
       }
       else if (length >= LARGE_ARRAY_SIZE) {
-        var set = createSet(array);
+        var set = iteratee ? null : createSet(array);
         if (set) {
           return setToArray(set);
         }