diff --git a/.github/workflows/test-windows.yml b/.github/workflows/test-windows.yml
index dd3e6422c..6b8b10445 100644
--- a/.github/workflows/test-windows.yml
+++ b/.github/workflows/test-windows.yml
@@ -63,6 +63,11 @@ jobs:
     - name: pip install wheel pytest pytest-cov
       run: python -m pip install wheel pytest pytest-cov
 
+    # TODO Remove when 3.9-dev includes setuptools 49.3.2+:
+    - name: Upgrade setuptools
+      if: "contains(matrix.python-version, '3.9-dev')"
+      run: python -m pip install -U "setuptools>=49.3.2"
+
     - name: Prepare dependencies
       run: |
         7z x winbuild\depends\nasm-2.14.02-win64.zip "-o$env:RUNNER_WORKSPACE\"