diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index a3e0254067..039baaa09e 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -42,6 +42,9 @@ Babel is built for node 4 and up but we develop using node 6. Make sure you are
 
 You can check this with `node -v` and `npm -v`.
 
+In addition, make sure that Yarn is installed.
+Installation instructions can be found here: https://yarnpkg.com/en/docs/install.
+
 #### Setup
 
 ```sh