diff --git a/.github/workflows/build_qt6.yml b/.github/workflows/build_qt6.yml
new file mode 100644
index 0000000000..5efb2dccf3
--- /dev/null
+++ b/.github/workflows/build_qt6.yml
@@ -0,0 +1,151 @@
+name: Qt6 Build Matrix
+# Many thanks to Cristian Adam for examples
+# e.g. https://github.com/cristianadam/HelloWorld/blob/master/.github/workflows/build_cmake.yml
+# https://cristianadam.eu/20191222/using-github-actions-with-c-plus-plus-and-cmake/
+
+
+on: [push, pull_request, workflow_dispatch]
+
+env:
+  QT_VERSION: 6.5.3
+  # this is different from MACOSX_DEPLOYMENT_TARGET to prevent build problems
+  # we set MACOSX_DEPLOYMENT_TARGET later
+  MACOS_TARGET: 10.15
+  FEATURES: -DBUILD_GPL_PLUGINS=ON -DWITH_COORDGEN=OFF -DUSE_VTK=ON -DQT_VERSION=6
+
+jobs:
+  build:
+    name: ${{ matrix.config.name }}
+    runs-on: ${{ matrix.config.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        config:
+        - {
+            name: "Ubuntu Qt6", artifact: "",
+            os: ubuntu-latest,
+            cc: "gcc", cxx: "g++",
+            build_type: "Release",
+            cmake_flags: "-G Ninja",
+            cpack: "",
+          }
+        - {
+            name: "Ubuntu Qt6 AppImage", artifact: "",
+            os: ubuntu-20.04,
+            cc: "gcc", cxx: "g++",
+            build_type: "Release",
+            cmake_flags: "-G Ninja -DINSTALL_BUNDLE_FILES=ON",
+            cpack: "",
+          }
+        - {
+            name: "macOS Qt6", artifact: "",
+            os: macos-latest,
+            cc: "clang", cxx: "clang++",
+            build_type: "Release",
+            cmake_flags: "-G Ninja",
+            cpack_flags: "-G DragNDrop",
+          }
+        - {
+            name: "Windows Qt6", artifact: "",
+            os: windows-latest,
+            cc: "cl", cxx: "cl",
+            build_type: "Release",
+            cmake_flags: "",
+            build_flags: "-j 2",
+            cpack_flags: "-G NSIS",
+          }
+
+    steps:
+
+    - name: Install Dependencies (Linux)
+      if: runner.os == 'Linux'
+      run: |
+        sudo apt-get -qq update
+        sudo apt-get -qq install ninja-build libeigen3-dev libboost-all-dev libglew-dev libxml2-dev
+    - name: Install Dependencies (macOS)
+      if: runner.os == 'macOS'
+      run: |
+        if uname -p | grep -q "arm" ; then
+           export PATH=/opt/homebrew/bin:$PATH
+        else # not self-hosted runner
+          brew install ninja eigen glew
+        fi
+    - name: Install Dependencies (Windows)
+      if: runner.os == 'Windows'
+      run: choco install ninja
+
+    - name: Checkout openchemistry
+      uses: actions/checkout@v3
+      with:
+        repository: openchemistry/openchemistry
+        submodules: recursive
+
+    - name: Checkout avogadroapp
+      uses: actions/checkout@v3
+      with:
+        repository: openchemistry/avogadroapp
+        path: avogadroapp
+
+    - name: Checkout avogadrolibs
+      uses: actions/checkout@v3
+      with:
+        path: avogadrolibs
+
+    - name: Install Qt
+      uses: jurplel/install-qt-action@v3
+      with:
+        cache: true
+        version: ${{ env.QT_VERSION }}
+        aqtversion: '==3.1.*'
+        modules: 'qt5compat'
+
+    - name: Configure MSVC Command Prompt
+      if: runner.os == 'Windows'
+      uses: ilammy/msvc-dev-cmd@v1
+      with:
+        arch: x64
+
+    - name: Grab cache files
+      uses: actions/cache@v3
+      if: runner.os != 'Windows'
+      with:
+        path: |
+          ${{ runner.workspace }}/build/thirdparty
+          ${{ runner.workspace }}/build/Downloads
+        key: ${{ matrix.config.name }}-thirdparty
+
+    - name: Configure
+      run: |
+        if [ ! -d "${{ runner.workspace }}/build" ]; then mkdir "${{ runner.workspace }}/build"; fi
+        cd "${{ runner.workspace }}/build"
+        # won't have any effect except on Mac
+        echo "MACOSX_DEPLOYMENT_TARGET=${{ env.MACOS_TARGET }}" >> $GITHUB_ENV
+        CC=${{matrix.config.cc}} CXX=${{matrix.config.cxx}} cmake $GITHUB_WORKSPACE ${{env.FEATURES}} -DCMAKE_BUILD_TYPE=${{matrix.config.build_type}} ${{matrix.config.cmake_flags}}
+      shell: bash
+
+    - name: Build
+      run: |
+        CC=${{matrix.config.cc}} CXX=${{matrix.config.cxx}} cmake --build . --config ${{matrix.config.build_type}} ${{matrix.config.build_flags}}
+      shell: bash
+      working-directory: ${{ runner.workspace }}/build
+
+    - name: Run tests
+      if: matrix.config.os == 'ubuntu-latest'
+      shell: cmake -P {0}
+      run: |
+        include(ProcessorCount)
+        ProcessorCount(N)
+        set(ENV{CTEST_OUTPUT_ON_FAILURE} "ON")
+        set(ENV{ASAN_OPTIONS} "new_delete_type_mismatch=0")
+        execute_process(
+          COMMAND ctest -j ${N}
+          WORKING_DIRECTORY ${{ runner.workspace }}/build/avogadrolibs
+          RESULT_VARIABLE result
+        )
+        if (NOT result EQUAL 0)
+          message(FATAL_ERROR "Running tests failed!")
+        endif()
+
+    - name: Setup tmate session
+      if: ${{ failure() }}
+      uses: mxschmitt/action-tmate@v3
diff --git a/avogadro/qtplugins/CMakeLists.txt b/avogadro/qtplugins/CMakeLists.txt
index 4666ea6716..8768ea91e9 100644
--- a/avogadro/qtplugins/CMakeLists.txt
+++ b/avogadro/qtplugins/CMakeLists.txt
@@ -191,7 +191,7 @@ if (USE_OPENGL)
 endif()
 
 # other optional plugins
-if(BUILD_GPL_PLUGINS)
+if(BUILD_GPL_PLUGINS AND QT_VERSION EQUAL 5)
   # qtaimcurvature.h/cpp contains GPL licensed code:
   add_subdirectory(qtaim)
 endif()