diff --git a/doc/source/rllib.rst b/doc/source/rllib.rst
index 0f7fd7cd1..937d4d6f3 100644
--- a/doc/source/rllib.rst
+++ b/doc/source/rllib.rst
@@ -23,7 +23,7 @@ RLlib has extra dependencies on top of ``ray``. First, you'll need to install ei
 
 .. code-block:: bash
 
-  pip install ray[rllib]  # also recommended: ray[debug]
+  pip install 'ray[rllib]'  # also recommended: ray[debug]
 
 Then, you can try out training in the following equivalent ways: