diff --git a/README.md b/README.md
index da6dbaf7b..d84218e69 100644
--- a/README.md
+++ b/README.md
@@ -98,6 +98,8 @@ we recommend cloning into your `${HOME}`, to avoid having to specify the
 ```bash
 $ git clone https://github.com/WebAssembly/binaryen ~/binaryen
 $ cd ~/binaryen
+$ git submodule init
+$ git submodule update
 $ cmake . && make
 ```