diff --git a/AK/RedBlackTree.h b/AK/RedBlackTree.h
index adce1cc5f7..b9ae98adfe 100644
--- a/AK/RedBlackTree.h
+++ b/AK/RedBlackTree.h
@@ -486,6 +486,8 @@ public:
     ConstIterator find_largest_not_above_iterator(K key) const
     {
         auto node = static_cast<Node*>(BaseTree::find_largest_not_above(this->m_root, key));
+        if (!node)
+            return end();
         return ConstIterator(node, static_cast<Node*>(BaseTree::predecessor(node)));
     }