diff --git a/requirements.txt b/requirements.txt
index 845ce49..91b3dc4 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -11,6 +11,7 @@ sphinx_dropdown_toggle
 git+https://github.com/TeachBooks/sphinx-togglebutton #waiting for merge of https://github.com/executablebooks/sphinx-togglebutton/pull/66, after, replace this line with `sphinx-dropdown-toggle`
 git+https://github.com/TeachBooks/sphinx-proof #waiting for merge of https://github.com/executablebooks/sphinx-proof/pull/146, after, replace this line with `sphinx-proof`
 sphinx-code-examples
+sphinx-accessibility
 
 # Now list the packages you want to download directly from GitHub
 git+https://github.com/TeachBooks/Sphinx-Thebe