diff --git a/pyproject.toml b/pyproject.toml
index 506db4c..1747143 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -13,7 +13,7 @@ dependencies = ["fenics-dolfinx>=0.8.0"]
 [project.optional-dependencies]
 test = ["pytest", "coverage", "ipyparallel"]
 dev = ["pdbpp", "ipython", "mypy", "ruff"]
-docs = ["jupyter-book", "ipyparallel", "ipywidgets"]
+docs = ["jupyter-book", "ipyparallel", "ipywidgets", "jupytext"]
 all = ["adios4dolfinx[test,dev,docs]"]
 
 [tool.pytest.ini_options]