diff --git a/builtin/array.mbt b/builtin/array.mbt
index 80cabed2..1036bfaf 100644
--- a/builtin/array.mbt
+++ b/builtin/array.mbt
@@ -843,13 +843,9 @@ pub fn dedup[T : Eq](self : Array[T]) -> Unit {
 /// v.unique() // v = [3, 4, 5, 6, 4]
 /// ```
 pub fn unique[T : Eq](self : Array[T]) -> Unit {
-  for i in 0..<self.length() {
-    for j = i + 1; j < self.length(); j = j + 1 {
-      if self[i] == self[j] {
-        self.remove(j) |> ignore
-      } else {
-        break
-      }
+  for i = 0; i < self.length(); i = i + 1 {
+    while i + 1 < self.length() && self[i] == self[i + 1] {
+      self.remove(i + 1) |> ignore
     }
   }
 }