diff --git a/lib/std/collections/list.c3 b/lib/std/collections/list.c3
index c6e47ffcb..435aafc65 100644
--- a/lib/std/collections/list.c3
+++ b/lib/std/collections/list.c3
@@ -240,7 +240,7 @@ fn void List.push_front(&self, Type type) @inline
 }
 
 /**
- * @require index < self.size
+ * @require index <= self.size
  **/
 fn void List.insert_at(&self, usz index, Type type)
 {
diff --git a/releasenotes.md b/releasenotes.md
index 411073ed8..c1b3583d0 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -79,6 +79,7 @@
 - Bug converting untyped list #1360.
 - Benchmark / test no longer suppresses debug info. #1364.
 - Bug when compile time subtracting a distinct type.
+- `insert_at` incorrectly prevented inserts at the end of a list.
 
 ### Stdlib changes