diff --git a/.github/workflows/unit-test.yaml b/.github/workflows/unit-test.yaml
index 2c44b15..c01c910 100644
--- a/.github/workflows/unit-test.yaml
+++ b/.github/workflows/unit-test.yaml
@@ -86,8 +86,10 @@ jobs:
             ${{ hashFiles('setup.py', 'dev-requirements.txt', '.github/workflows/unit-test.yaml') }}
 
       - name: Install Python dependencies
+        # Keep pip version pinning in sync with the one in bootstrap.py!
+        # See changelog at https://pip.pypa.io/en/latest/news/#changelog
         run: |
-          python3 -m pip install -U pip
+          python3 -m pip install -U "pip==21.3.*"
           python3 -m pip install -r dev-requirements.txt
           python3 -m pip install -e .
           pip freeze
diff --git a/bootstrap/bootstrap.py b/bootstrap/bootstrap.py
index 563138a..dc1309f 100644
--- a/bootstrap/bootstrap.py
+++ b/bootstrap/bootstrap.py
@@ -334,8 +334,10 @@ def main():
 
 
     # Upgrade pip
+    # Keep pip version pinning in sync with the one in unit-test.yml!
+    # See changelog at https://pip.pypa.io/en/latest/news/#changelog
     logger.info('Upgrading pip...')
-    run_subprocess([pip_bin, 'install', '--upgrade', 'pip'])
+    run_subprocess([pip_bin, 'install', '--upgrade', 'pip==21.3.*'])
 
 
     # Install/upgrade TLJH installer