diff --git a/.github/workflows/pypi-publish.yml b/.github/workflows/pypi-publish.yml
index 1eff76cef..f28d8817b 100644
--- a/.github/workflows/pypi-publish.yml
+++ b/.github/workflows/pypi-publish.yml
@@ -15,7 +15,7 @@ jobs:
     - name: Set up Python
       uses: actions/setup-python@v1
       with:
-        python-version: '3.x'
+        python-version: '3.10'  # 3.11 breaks grpcio-tools.
     - name: Install dependencies
       run: |
         sudo apt-get install -y libprotobuf-dev