diff --git a/docs/docsite/rst/user_guide/playbooks_variables.rst b/docs/docsite/rst/user_guide/playbooks_variables.rst
index d099a52d4c0..6ef7f99e378 100644
--- a/docs/docsite/rst/user_guide/playbooks_variables.rst
+++ b/docs/docsite/rst/user_guide/playbooks_variables.rst
@@ -30,6 +30,8 @@ Variable names should be letters, numbers, and underscores.  Variables should al
 
 ``foo-port``, ``foo port``, ``foo.port`` and ``12`` are not valid variable names.
 
+`Python keywords <https://docs.python.org/3/reference/lexical_analysis.html#keywords>`_  such as ``async`` and ``lambda`` are not valid variable names and thus must be avoided.
+
 YAML also supports dictionaries which map keys to values.  For instance::
 
   foo: