diff --git a/setup.py b/setup.py
index 222f27a8cf..0f6b8b8eb8 100755
--- a/setup.py
+++ b/setup.py
@@ -77,9 +77,9 @@ def make_console_script(name):
 }
 
 extras_require["doc"] = [
-    "sphinx >= 1.8",
     # Force ReadTheDocs to use a recent version, rather than the defaults used
     # for old projects.
+    "sphinx > 2",
     "sphinx_rtd_theme >= 0.5.2",
     "sphinxcontrib-plantuml",
     "nbsphinx",