diff --git a/src/util/ListUtil.re b/src/util/ListUtil.re
index 39a2d5994e..8481df4f0a 100644
--- a/src/util/ListUtil.re
+++ b/src/util/ListUtil.re
@@ -9,9 +9,6 @@ let dedup_f = (f, xs) =>
 
 let dedup = xs => dedup_f((==), xs);
 
-let are_duplicates = xs =>
-  List.length(List.sort_uniq(compare, xs)) == List.length(xs);
-
 /**
   Groups elements of a list by a specified key.
 
diff --git a/test/Test_ListUtil.re b/test/Test_ListUtil.re
index 017c2e6d96..9abfca4f07 100644
--- a/test/Test_ListUtil.re
+++ b/test/Test_ListUtil.re
@@ -46,22 +46,6 @@ let tests = (
         ); // TODO: Interesting the order here is messed up because of fold_right
       },
     ),
-    test_case(
-      "are_duplicates has duplicates",
-      `Quick,
-      () => {
-        let xs = [1, 2, 3, 2];
-        check(bool, "Returns false", false, ListUtil.are_duplicates(xs)); // TODO: Interesting the order here is messed up because of fold_right
-      },
-    ),
-    test_case(
-      "are_duplicates has no duplicates",
-      `Quick,
-      () => {
-        let xs = [1, 2, 3];
-        check(bool, "Returns true", true, ListUtil.are_duplicates(xs));
-      },
-    ),
     test_case(
       "group_by with constant function preserves list",
       `Quick,