diff --git a/.github/workflows/build_deploy.yml b/.github/workflows/build_deploy.yml
index f2a14f4..b2604e7 100644
--- a/.github/workflows/build_deploy.yml
+++ b/.github/workflows/build_deploy.yml
@@ -9,6 +9,9 @@ jobs:
   test:
     uses: ./.github/workflows/test_pyqt5.yml
 
+  test_pyqt6:
+    uses: ./.github/workflows/test_pyqt6.yml
+
   build_wheels:
     name: Build wheels on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
@@ -57,7 +60,7 @@ jobs:
           path: dist/*.tar.gz
 
   upload_pypi:
-    needs: [test, build_wheels, build_sdist]
+    needs: [test, test_pyqt6, build_wheels, build_sdist]
     runs-on: ubuntu-latest
     environment: pypi
     permissions:
diff --git a/.github/workflows/test_pyqt5.yml b/.github/workflows/test_pyqt5.yml
index 8edb2bc..ecc0b1b 100644
--- a/.github/workflows/test_pyqt5.yml
+++ b/.github/workflows/test_pyqt5.yml
@@ -22,7 +22,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.10", "3.13", "3.14"]
+        python-version: ["3.10", "3.14"]
 
     steps:
     - uses: actions/checkout@v7
@@ -31,6 +31,9 @@ jobs:
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
+      env:
+        # Pull requests are routed by their target branch, pushes by their own branch
+        TARGET_BRANCH: ${{ github.base_ref || github.ref_name }}
       run: |
         sudo apt install libxkbcommon-x11-0 libxcb-icccm4 libxcb-image0 libxcb-keysyms1 libxcb-randr0 libxcb-render-util0 libxcb-xinerama0 libxcb-xfixes0 x11-utils
         /sbin/start-stop-daemon --start --quiet --pidfile /tmp/custom_xvfb_99.pid --make-pidfile --background --exec /usr/bin/Xvfb -- :99 -screen 0 1920x1200x24 -ac +extension GLX
@@ -38,7 +41,7 @@ jobs:
         python -m pip install ruff pytest
         pip install PyQt5 setuptools numpy Cython
         python setup.py build_ext --inplace
-        if [ "${{ github.ref_name }}" = "develop" ]; then
+        if [ "$TARGET_BRANCH" = "develop" ]; then
            pip uninstall -y guidata PythonQwt
            cd ..
            git clone --depth 1 --branch develop https://github.com/PlotPyStack/guidata.git
@@ -53,7 +56,7 @@ jobs:
            pip install -r deps.txt
            # Install PlotPy without dependencies
            pip install --no-deps .
-        elif [ "${{ github.ref_name }}" = "release" ]; then
+        elif [ "$TARGET_BRANCH" = "release" ]; then
            pip uninstall -y guidata PythonQwt
            cd ..
            # Try cloning guidata from release, fallback to main or master
diff --git a/.github/workflows/test_pyqt6.yml b/.github/workflows/test_pyqt6.yml
new file mode 100644
index 0000000..a75650c
--- /dev/null
+++ b/.github/workflows/test_pyqt6.yml
@@ -0,0 +1,85 @@
+# This workflow will install Python dependencies, run tests and lint with a variety of Python versions
+# For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-python
+
+# Inspired from https://pytest-qt.readthedocs.io/en/latest/troubleshooting.html#github-actions
+
+name: Build, install and test with PyQt6
+
+on:
+  push:
+    branches: [ "master", "develop", "release" ]
+  pull_request:
+    branches: [ "master", "develop", "release" ]
+  workflow_call:
+
+jobs:
+  build:
+
+    env:
+      DISPLAY: ':99.0'
+
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.10", "3.14"]
+
+    steps:
+    - uses: actions/checkout@v7
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v7
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Install dependencies
+      env:
+        # Pull requests are routed by their target branch, pushes by their own branch
+        TARGET_BRANCH: ${{ github.base_ref || github.ref_name }}
+      run: |
+        sudo apt install libxkbcommon-x11-0 libxcb-icccm4 libxcb-image0 libxcb-keysyms1 libxcb-randr0 libxcb-render-util0 libxcb-xinerama0 libxcb-xfixes0 x11-utils libegl1 libgl1 libopengl0 libxcb-cursor0
+        /sbin/start-stop-daemon --start --quiet --pidfile /tmp/custom_xvfb_99.pid --make-pidfile --background --exec /usr/bin/Xvfb -- :99 -screen 0 1920x1200x24 -ac +extension GLX
+        python -m pip install --upgrade pip
+        python -m pip install ruff pytest
+        pip install PyQt6 setuptools numpy Cython
+        python setup.py build_ext --inplace
+        if [ "$TARGET_BRANCH" = "develop" ]; then
+           pip uninstall -y guidata PythonQwt
+           cd ..
+           git clone --depth 1 --branch develop https://github.com/PlotPyStack/guidata.git
+           git clone --depth 1 https://github.com/PlotPyStack/PythonQwt.git
+           cd PlotPy
+           pip install -e ../guidata
+           pip install -e ../PythonQwt
+           # Install tomli for TOML parsing (safe if already present)
+           pip install tomli
+           # Extract dependencies and save to file, then install
+           python -c "import tomli; f=open('pyproject.toml','rb'); data=tomli.load(f); deps=[d for d in data['project']['dependencies'] if not any(p in d for p in ['guidata', 'PythonQwt'])]; open('deps.txt','w').write('\n'.join(deps))"
+           pip install -r deps.txt
+           # Install PlotPy without dependencies
+           pip install --no-deps .
+        elif [ "$TARGET_BRANCH" = "release" ]; then
+           pip uninstall -y guidata PythonQwt
+           cd ..
+           # Try cloning guidata from release, fallback to main or master
+           git clone --depth 1 --branch release https://github.com/PlotPyStack/guidata.git || git clone --depth 1 https://github.com/PlotPyStack/guidata.git || git clone --depth 1 --branch master https://github.com/PlotPyStack/guidata.git
+           # Try cloning PythonQwt from main or master
+           git clone --depth 1 https://github.com/PlotPyStack/PythonQwt.git || git clone --depth 1 --branch master https://github.com/PlotPyStack/PythonQwt.git
+           cd PlotPy
+           pip install -e ../guidata
+           pip install -e ../PythonQwt
+           # Install tomli for TOML parsing (safe if already present)
+           pip install tomli
+           # Extract dependencies and save to file, then install
+           python -c "import tomli; f=open('pyproject.toml','rb'); data=tomli.load(f); deps=[d for d in data['project']['dependencies'] if not any(p in d for p in ['guidata', 'PythonQwt'])]; open('deps.txt','w').write('\n'.join(deps))"
+           pip install -r deps.txt
+           # Install PlotPy without dependencies
+           pip install --no-deps .
+        else
+           # Install from PyPI normally for master branch
+           pip install .[test]
+        fi
+    - name: Lint with Ruff
+      run: ruff check --output-format=github plotpy
+    - name: Test with pytest
+      run: |
+        pytest
diff --git a/.github/workflows/test_pyside6.yml b/.github/workflows/test_pyside6.yml
new file mode 100644
index 0000000..07f7e04
--- /dev/null
+++ b/.github/workflows/test_pyside6.yml
@@ -0,0 +1,86 @@
+# This workflow will install Python dependencies, run tests and lint with a variety of Python versions
+# For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-python
+
+# Inspired from https://pytest-qt.readthedocs.io/en/latest/troubleshooting.html#github-actions
+
+name: Build, install and test with PySide6
+
+on:
+  push:
+    branches: [ "master", "develop", "release" ]
+  pull_request:
+    branches: [ "master", "develop", "release" ]
+  workflow_call:
+
+jobs:
+  build:
+
+    env:
+      DISPLAY: ':99.0'
+
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.10", "3.14"]
+
+    steps:
+    - uses: actions/checkout@v7
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v7
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Install dependencies
+      env:
+        # Pull requests are routed by their target branch, pushes by their own branch
+        TARGET_BRANCH: ${{ github.base_ref || github.ref_name }}
+      run: |
+        sudo apt install libxkbcommon-x11-0 libxcb-icccm4 libxcb-image0 libxcb-keysyms1 libxcb-randr0 libxcb-render-util0 libxcb-xinerama0 libxcb-xfixes0 x11-utils libegl1 libgl1 libopengl0 libxcb-cursor0
+        /sbin/start-stop-daemon --start --quiet --pidfile /tmp/custom_xvfb_99.pid --make-pidfile --background --exec /usr/bin/Xvfb -- :99 -screen 0 1920x1200x24 -ac +extension GLX
+        python -m pip install --upgrade pip
+        python -m pip install ruff pytest
+        # PySide6 6.12.0 drops a reference to None on each void call: fatal before Python 3.12
+        pip install "PySide6!=6.12.0; python_version < '3.12'" "PySide6; python_version >= '3.12'" setuptools numpy Cython
+        python setup.py build_ext --inplace
+        if [ "$TARGET_BRANCH" = "develop" ]; then
+           pip uninstall -y guidata PythonQwt
+           cd ..
+           git clone --depth 1 --branch develop https://github.com/PlotPyStack/guidata.git
+           git clone --depth 1 https://github.com/PlotPyStack/PythonQwt.git
+           cd PlotPy
+           pip install -e ../guidata
+           pip install -e ../PythonQwt
+           # Install tomli for TOML parsing (safe if already present)
+           pip install tomli
+           # Extract dependencies and save to file, then install
+           python -c "import tomli; f=open('pyproject.toml','rb'); data=tomli.load(f); deps=[d for d in data['project']['dependencies'] if not any(p in d for p in ['guidata', 'PythonQwt'])]; open('deps.txt','w').write('\n'.join(deps))"
+           pip install -r deps.txt
+           # Install PlotPy without dependencies
+           pip install --no-deps .
+        elif [ "$TARGET_BRANCH" = "release" ]; then
+           pip uninstall -y guidata PythonQwt
+           cd ..
+           # Try cloning guidata from release, fallback to main or master
+           git clone --depth 1 --branch release https://github.com/PlotPyStack/guidata.git || git clone --depth 1 https://github.com/PlotPyStack/guidata.git || git clone --depth 1 --branch master https://github.com/PlotPyStack/guidata.git
+           # Try cloning PythonQwt from main or master
+           git clone --depth 1 https://github.com/PlotPyStack/PythonQwt.git || git clone --depth 1 --branch master https://github.com/PlotPyStack/PythonQwt.git
+           cd PlotPy
+           pip install -e ../guidata
+           pip install -e ../PythonQwt
+           # Install tomli for TOML parsing (safe if already present)
+           pip install tomli
+           # Extract dependencies and save to file, then install
+           python -c "import tomli; f=open('pyproject.toml','rb'); data=tomli.load(f); deps=[d for d in data['project']['dependencies'] if not any(p in d for p in ['guidata', 'PythonQwt'])]; open('deps.txt','w').write('\n'.join(deps))"
+           pip install -r deps.txt
+           # Install PlotPy without dependencies
+           pip install --no-deps .
+        else
+           # Install from PyPI normally for master branch
+           pip install .[test]
+        fi
+    - name: Lint with Ruff
+      run: ruff check --output-format=github plotpy
+    - name: Test with pytest
+      run: |
+        pytest
diff --git a/doc/release_notes/release_2.12.md b/doc/release_notes/release_2.12.md
index e932697..ece84d3 100644
--- a/doc/release_notes/release_2.12.md
+++ b/doc/release_notes/release_2.12.md
@@ -24,3 +24,8 @@
 ⚙️ Dependencies:
 
 * Python 3.10 or later is now required, and wheels are no longer built for Python 3.9. Python 3.9 users must keep an earlier compatible release (PlotPy 2.11.x) (closes [Issue #74](https://github.com/PlotPyStack/PlotPy/issues/74))
+
+🔧 Other changes:
+
+* **Continuous integration** — PlotPy is now also tested with PyQt6 and PySide6 (Python 3.10 and 3.14) on each push and pull request, and with PyQt6 before each PyPI release. Pull requests targeting the `develop` or `release` branch are now tested against the development versions of guidata and PythonQwt, as pushes to these branches already were (closes [Issue #69](https://github.com/PlotPyStack/PlotPy/issues/69))
+* **Test suite** — The `SnapshotTool` annotation test no longer hangs when run on its own, on Windows or with Qt 6: it waited indefinitely for the snapshot dialog to be closed
diff --git a/plotpy/tests/unit/test_annotation_tools.py b/plotpy/tests/unit/test_annotation_tools.py
index fb0c667..a32f2f1 100644
--- a/plotpy/tests/unit/test_annotation_tools.py
+++ b/plotpy/tests/unit/test_annotation_tools.py
@@ -5,6 +5,7 @@
 import numpy as np
 import pytest
 from guidata.qthelpers import exec_dialog, execenv, qt_app_context
+from qtpy import QtWidgets as QW
 
 from plotpy.interfaces.items import IBasePlotItem, IShapeItemType
 from plotpy.tests import vistools as ptv
@@ -97,13 +98,29 @@ def _test_annotation_tools(tool_classes: tuple[type[InteractiveTool], ...]):
         for tool_class in tool_classes:
             tool = win.manager.get_tool(tool_class)
             assert tool is not None
+            snapshot_calls: list[tuple] | None = None
+            if execenv.unattended and isinstance(tool, SnapshotTool):
+                # The snapshot action opens modal dialogs (destination size, options,
+                # file name) which are never closed in unattended mode
+                snapshot_calls = []
+                tool.action_func = lambda *args, calls=snapshot_calls: calls.append(
+                    args
+                )
             tool.activate()
             x_path = np.linspace(0, 0.5, 100)
             y_path = np.linspace(0, 0.5, 100)
             with execenv.context(accept_dialogs=True):
                 drag_mouse(win, x_path, y_path)
+            # Run the actions deferred by a zero-delay timer (e.g. the snapshot
+            # action) within this test rather than in a later event loop
+            QW.QApplication.processEvents()
             if hasattr(tool_class, "SWITCH_TO_DEFAULT_TOOL"):
                 assert win.manager.get_default_tool() == default_tool
+            if snapshot_calls is not None:
+                assert len(snapshot_calls) == 1
+                snap_plot, p0, p1 = snapshot_calls[0]
+                assert snap_plot is plot
+                assert p0.x() < p1.x() and p0.y() < p1.y()
         plot.unselect_all()
         shape_items: list[IBasePlotItem] = plot.get_items(item_type=IShapeItemType)
         plot.select_some_items(shape_items)