diff --git a/doc/testing_with_selenium.md b/doc/testing_with_selenium.md
index d83e274b162..7f85a45d9ab 100644
--- a/doc/testing_with_selenium.md
+++ b/doc/testing_with_selenium.md
@@ -35,7 +35,7 @@ Gerrit host. See the README for details.
 the tests in. Homebrew is the easiest way to go:
 
 ```sh
-brew cask install chromedriver # necessary for running tests in Chrome
+brew install chromedriver --cask # necessary for running tests in Chrome
 brew install geckodriver # necessary for running tests in Firefox
 ```