diff --git a/README.rst b/README.rst
index 1b0040cde..6ad7dc408 100644
--- a/README.rst
+++ b/README.rst
@@ -55,7 +55,7 @@ Traits has the following optional dependencies:
 
 To build the full documentation one needs:
 
-* `Sphinx <https://pypi.org/project/Sphinx>`_ version 1.8 or later.
+* `Sphinx <https://pypi.org/project/Sphinx>`_ version 2.1 or later.
 * The `Enthought Sphinx Theme <https://pypi.org/project/enthought-sphinx-theme>`_.
   (A version of the documentation can be built without this, but
   some formatting may be incorrect.)
diff --git a/etstool.py b/etstool.py
index 34e7630ff..7ef15ec2a 100644
--- a/etstool.py
+++ b/etstool.py
@@ -93,7 +93,7 @@
     "mypy",
     "numpy",
     "pyqt5",
-    "Sphinx!=3.2.0",
+    "Sphinx",
     "traitsui",
 }
 
diff --git a/setup.py b/setup.py
index 137dc946f..b5c768ee1 100644
--- a/setup.py
+++ b/setup.py
@@ -301,14 +301,14 @@ def get_long_description():
     extras_require={
         "docs": [
             "enthought-sphinx-theme",
-            "Sphinx!=3.2.0",
+            "Sphinx>=2.1.0,!=3.2.0",
         ],
         "test": [
             "Cython",
             "flake8",
             "mypy",
             "setuptools",
-            "Sphinx!=3.2.0",
+            "Sphinx>=2.1.0,!=3.2.0",
             # Python 3.9 exclusions:
             #
             # * NumPy installation fails on Python 3.9 on the Ubuntu Xenial