diff --git a/.github/workflows/sphinx.yml b/.github/workflows/sphinx.yml
index ef0ea0a2..cbde0945 100644
--- a/.github/workflows/sphinx.yml
+++ b/.github/workflows/sphinx.yml
@@ -10,7 +10,7 @@ jobs:
       - uses: actions/setup-python@v3
       - name: Install dependencies
         run: |
-          pip install sphinx sphinx_rtd_theme furo sphinx_copybutton docutils sphinx_inline_tabs sphinx_removed_in
+          pip install sphinx sphinx_rtd_theme furo sphinx_copybutton docutils sphinx_inline_tabs sphinx_removed_in sphinxext
       - name: Sphinx build
         run: |
           sphinx-build -b html docs/source/ docs/build/html