diff --git a/.github/workflows/pythonpublish.yml b/.github/workflows/pythonpublish.yml
index 69d80336..20268fb7 100644
--- a/.github/workflows/pythonpublish.yml
+++ b/.github/workflows/pythonpublish.yml
@@ -1,76 +1,85 @@
 name: Upload Python Package
 
 on:
   push:
     tags:
       - dulwich-*
 
 jobs:
   deploy:
 
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
         os: [macos-latest, windows-latest]
         python-version: ['3.5', '3.6', '3.7', '3.8', '3.9']
         include:
           - os: ubuntu-latest
             python-version: '3.x'
           # path encoding
         exclude:
           - os: windows-latest
             python-version: 3.5
           - os: macos-latest
             python-version: 3.5
       fail-fast: false
 
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v2
       with:
         python-version: ${{ matrix.python-version }}
+    - name: Install native dependencies (Ubuntu)
+      run: sudo apt-get update && sudo apt-get install -y libgpgme-dev libgpg-error-dev
+      if: "matrix.os == 'ubuntu-latest'"
+    - name: Install native dependencies (MacOS)
+      run: brew install swig gpgme
+      if: "matrix.os == 'macos-latest'"
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
         pip install setuptools wheel twine fastimport
+    - name: Install gpg on supported platforms
+      run: pip install -U gpg
+      if: "matrix.os != 'windows-latest' && matrix.python-version != 'pypy3'"
     - name: Run test suite
       run: |
         python -m unittest dulwich.tests.test_suite
     - name: Build
       run: |
         python setup.py sdist bdist_wheel
       if: "matrix.os != 'ubuntu-latest'"
     - uses: docker/setup-qemu-action@v1
       name: Set up QEMU
       if: "matrix.os == 'ubuntu-latest'"
     - name: Build and publish (Linux aarch64)
       uses: RalfG/python-wheels-manylinux-build@v0.3.3-manylinux2014_aarch64
       with:
         python-versions: 'cp36-cp36m cp37-cp37m cp38-cp38 cp39-cp39'
       if: "matrix.os == 'ubuntu-latest'"
     - name: Build and publish (Linux)
       uses: RalfG/python-wheels-manylinux-build@v0.3.1
       with:
         python-versions: 'cp36-cp36m cp37-cp37m cp38-cp38 cp39-cp39'
       env:
         # Temporary fix for LD_LIBRARY_PATH issue. See
         # https://github.com/RalfG/python-wheels-manylinux-build/issues/26
         LD_LIBRARY_PATH: /usr/local/lib:${{ env.LD_LIBRARY_PATH }}
       if: "matrix.os == 'ubuntu-latest'"
     - name: Publish (Linux)
       env:
         TWINE_USERNAME: ${{ secrets.PYPI_USERNAME }}
         TWINE_PASSWORD: ${{ secrets.PYPI_PASSWORD }}
       run: |
         # Only include *manylinux* wheels; the other wheels files are built but
         # rejected by pip.
         twine upload dist/*manylinux*.whl
       if: "matrix.os == 'ubuntu-latest'"
     - name: Publish
       env:
         TWINE_USERNAME: ${{ secrets.PYPI_USERNAME }}
         TWINE_PASSWORD: ${{ secrets.PYPI_PASSWORD }}
       run: |
         twine upload dist/*.whl
       if: "matrix.os != 'ubuntu-latest'"