diff --git a/courses/free-courses-en.md b/courses/free-courses-en.md
index 742bf301c..c3fd75df1 100644
--- a/courses/free-courses-en.md
+++ b/courses/free-courses-en.md
@@ -188,6 +188,7 @@
 * [Stanford University Algorithms: Design and Analysis, Part 1](https://online.stanford.edu/courses/soe-ycsalgorithms1-algorithms-design-and-analysis-part-1)
 * [Stanford University Algorithms: Design and Analysis, Part 2](https://online.stanford.edu/courses/soe-ycs0001-algorithms-design-and-analysis-part-2)
 * [Strivers A2Z-DSA Course \| DSA Playlist \| Placements](https://www.youtube.com/playlist?list=PLgUwDviBIf0oF6QL8m22w1hIDC1vJ_BHz) - take U forward
+* [Tree Algorithms](https://www.youtube.com/playlist?list=PLDV1Zeh2NRsDfGc8rbQ0_58oEZQVtvoIc) - WilliamFiset
 * [Trees by Striver \| C++ \| Java \| Placements \| Binary Trees and Traversals \| Problems](https://www.youtube.com/playlist?list=PLgUwDviBIf0q8Hkd7bK2Bpryj2xVJk8Vk) - take U forward