diff --git a/.readthedocs.yml b/.readthedocs.yml
index bc44d38b4..b506c5f40 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -2,9 +2,12 @@ version: 2
 
 python:
    install:
-      - requirements: doc/en/requirements.txt
-      - method: pip
-        path: .
+     # Install pytest first, then doc/en/requirements.txt.
+     # This order is important to honor any pins in doc/en/requirements.txt
+     # when the pinned library is also a dependency of pytest.
+     - method: pip
+       path: .
+     - requirements: doc/en/requirements.txt
 
 build:
   os: ubuntu-20.04
diff --git a/doc/en/requirements.txt b/doc/en/requirements.txt
index 0523772d4..b6059723c 100644
--- a/doc/en/requirements.txt
+++ b/doc/en/requirements.txt
@@ -5,3 +5,7 @@ sphinx-removed-in>=0.2.0
 sphinx>=5,<6
 sphinxcontrib-trio
 sphinxcontrib-svg2pdfconverter
+# Pin packaging because it no longer handles 'latest' version, which
+# is the version that is assigned to the docs.
+# See https://github.com/pytest-dev/pytest/pull/10578#issuecomment-1348249045.
+packaging <22