diff --git a/pyproject.toml b/pyproject.toml
index ba19ae5d..cbff99b9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -26,9 +26,9 @@ test = [
 ]
 docs = [
     "nbsphinx",
+    "sphinx<7.0",
     "stsci_rtd_theme",
     "sphinx-astropy",
-    "sphinx_rtd_theme",
     "sphinx-automodapi",
     "sphinx-issues",
     "tomli; python_version <\"3.11\"",
diff --git a/tox.ini b/tox.ini
index fc92d9d2..a2f52fbe 100644
--- a/tox.ini
+++ b/tox.ini
@@ -33,7 +33,6 @@ commands=
 basepython= python3.10
 deps=
     sphinx
-    sphinx_rtd_theme
     stsci_rtd_theme
     sphinx-automodapi
     sphinx-issues