diff --git a/Questions.md b/Questions.md
index ef6b2f2..e445589 100644
--- a/Questions.md
+++ b/Questions.md
@@ -21,4 +21,5 @@
 17. [Pow(x, n)](https://leetcode.com/problems/powx-n/description/) `Leetcode 150` `Striver`
 18. [Majority Element](https://leetcode.com/problems/majority-element/description/) `Leetcode 150` `Striver`
 19. [Longest Consecutive Sequence](https://leetcode.com/problems/longest-consecutive-sequence/description/) `Leetcode 150` `Striver`
+20. [Longest Substring Without Repeating Characters](https://leetcode.com/problems/longest-substring-without-repeating-characters/description/) `Leetcode 150` `Striver`