diff --git a/flake.nix b/flake.nix
index de4ed83d..b0f406cd 100644
--- a/flake.nix
+++ b/flake.nix
@@ -44,7 +44,7 @@
         paramiko
         plumbum
         pylpsd
-        pyqt5
+        pyqt6
         pyqtgraph
         pyrp3
         pytest
diff --git a/linien-gui/linien_gui/app.py b/linien-gui/linien_gui/app.py
index abda7037..4a108b35 100644
--- a/linien-gui/linien_gui/app.py
+++ b/linien-gui/linien_gui/app.py
@@ -27,8 +27,8 @@
 from linien_gui.ui.main_window import MainWindow
 from linien_gui.ui.psd_window import PSDWindow
 from linien_gui.ui.version_checker import VersionCheckerThread
-from PyQt5 import QtWidgets
-from PyQt5.QtCore import pyqtSignal
+from PyQt6 import QtWidgets
+from PyQt6.QtCore import pyqtSignal
 from pyqtgraph.Qt import QtCore
 
 sys.path += [str(UI_PATH)]
diff --git a/linien-gui/linien_gui/dialogs.py b/linien-gui/linien_gui/dialogs.py
index 30ee8c2b..e317c57d 100644
--- a/linien-gui/linien_gui/dialogs.py
+++ b/linien-gui/linien_gui/dialogs.py
@@ -18,8 +18,8 @@
 from typing import Callable
 
 from linien_client.device import Device
-from PyQt5.QtCore import pyqtSignal
-from PyQt5.QtWidgets import (
+from PyQt6.QtCore import pyqtSignal
+from PyQt6.QtWidgets import (
     QDialog,
     QListWidget,
     QMessageBox,
diff --git a/linien-gui/linien_gui/threads.py b/linien-gui/linien_gui/threads.py
index bab3963d..2d1a8d7a 100644
--- a/linien-gui/linien_gui/threads.py
+++ b/linien-gui/linien_gui/threads.py
@@ -31,7 +31,7 @@
 )
 from linien_client.remote_parameters import RemoteParameter
 from linien_common.communication import RestorableParameterValues
-from PyQt5.QtCore import QObject, QThread, pyqtSignal
+from PyQt6.QtCore import QObject, QThread, pyqtSignal
 
 logger = logging.getLogger(__name__)
 logger.setLevel(logging.DEBUG)
diff --git a/linien-gui/linien_gui/ui/device_manager.py b/linien-gui/linien_gui/ui/device_manager.py
index 9770595c..b33765fc 100644
--- a/linien-gui/linien_gui/ui/device_manager.py
+++ b/linien-gui/linien_gui/ui/device_manager.py
@@ -34,8 +34,8 @@
 from linien_gui.threads import ConnectionThread
 from linien_gui.ui.new_device_dialog import NewDeviceDialog
 from linien_gui.utils import get_linien_app_instance, set_window_icon
-from PyQt5 import QtCore, QtWidgets, uic
-from PyQt5.QtWidgets import QListWidget, QPushButton
+from PyQt6 import QtCore, QtWidgets, uic
+from PyQt6.QtWidgets import QListWidget, QPushButton
 
 
 class DeviceManager(QtWidgets.QMainWindow):
diff --git a/linien-gui/linien_gui/ui/general_panel.py b/linien-gui/linien_gui/ui/general_panel.py
index 53ff7ed1..65976bec 100644
--- a/linien-gui/linien_gui/ui/general_panel.py
+++ b/linien-gui/linien_gui/ui/general_panel.py
@@ -25,7 +25,7 @@
 from linien_gui.config import UI_PATH
 from linien_gui.ui.spin_box import CustomDoubleSpinBoxNoSign
 from linien_gui.utils import get_linien_app_instance, param2ui
-from PyQt5 import QtWidgets, uic
+from PyQt6 import QtWidgets, uic
 
 
 class GeneralPanel(QtWidgets.QWidget):
diff --git a/linien-gui/linien_gui/ui/lock_status_panel.py b/linien-gui/linien_gui/ui/lock_status_panel.py
index bb11b259..df6dc601 100644
--- a/linien-gui/linien_gui/ui/lock_status_panel.py
+++ b/linien-gui/linien_gui/ui/lock_status_panel.py
@@ -17,7 +17,7 @@
 # along with Linien.  If not, see <http://www.gnu.org/licenses/>.
 
 from linien_gui.utils import get_linien_app_instance, param2ui
-from PyQt5 import QtCore, QtWidgets
+from PyQt6 import QtCore, QtWidgets
 
 
 class LockStatusPanel(QtWidgets.QWidget):
diff --git a/linien-gui/linien_gui/ui/locking_panel.py b/linien-gui/linien_gui/ui/locking_panel.py
index 86d8c17a..437d4248 100644
--- a/linien-gui/linien_gui/ui/locking_panel.py
+++ b/linien-gui/linien_gui/ui/locking_panel.py
@@ -21,7 +21,7 @@
 from linien_gui.ui.lock_status_panel import LockStatusPanel
 from linien_gui.ui.spin_box import CustomSpinBox
 from linien_gui.utils import get_linien_app_instance, param2ui
-from PyQt5 import QtWidgets, uic
+from PyQt6 import QtWidgets, uic
 
 
 class LockingPanel(QtWidgets.QWidget):
diff --git a/linien-gui/linien_gui/ui/logging_panel.py b/linien-gui/linien_gui/ui/logging_panel.py
index 6256abcd..005b4d6b 100644
--- a/linien-gui/linien_gui/ui/logging_panel.py
+++ b/linien-gui/linien_gui/ui/logging_panel.py
@@ -21,8 +21,8 @@
 from linien_common.influxdb import InfluxDBCredentials
 from linien_gui.config import UI_PATH
 from linien_gui.utils import get_linien_app_instance
-from PyQt5 import QtWidgets, uic
-from PyQt5.QtCore import pyqtSignal
+from PyQt6 import QtWidgets, QtGui, uic
+from PyQt6.QtCore import pyqtSignal
 
 START_LOG_BUTTON_TEXT = "Start Logging"
 STOP_LOG_BUTTON_TEXT = "Stop Logging"
@@ -147,11 +147,11 @@ def create_menu_entries(self, parameters: RemoteParameters) -> None:
         param_dict = dict(sorted(param_dict.items()))  # sort alphabetically
         for name, param in param_dict.items():
             if param.loggable:
-                action = QtWidgets.QAction(name, parent=self, checkable=True)  # type: ignore[call-overload] # noqa: E501
+                action = QtGui.QAction(name, parent=self, checkable=True)  # type: ignore[call-overload] # noqa: E501
                 action.setChecked(param.log)
                 self.addAction(action)
         self.triggered.connect(self.on_item_selected)
 
-    def on_item_selected(self, action: QtWidgets.QAction) -> None:
+    def on_item_selected(self, action: QtGui.QAction) -> None:
         param_name = action.text()
         self.item_clicked.emit(param_name, action.isChecked())
diff --git a/linien-gui/linien_gui/ui/main_window.py b/linien-gui/linien_gui/ui/main_window.py
index 5ca799a2..478f2c20 100644
--- a/linien-gui/linien_gui/ui/main_window.py
+++ b/linien-gui/linien_gui/ui/main_window.py
@@ -30,7 +30,7 @@
 from linien_gui.ui.spin_box import CustomDoubleSpinBox
 from linien_gui.ui.sweep_control import SweepControlWidget, SweepSlider
 from linien_gui.utils import color_to_hex, get_linien_app_instance, set_window_icon
-from PyQt5 import QtWidgets, uic
+from PyQt6 import QtWidgets, uic
 
 ZOOM_STEP = 0.9
 MAX_ZOOM = 50
diff --git a/linien-gui/linien_gui/ui/modulation_sweep_panel.py b/linien-gui/linien_gui/ui/modulation_sweep_panel.py
index 4a48b820..2447b3a5 100644
--- a/linien-gui/linien_gui/ui/modulation_sweep_panel.py
+++ b/linien-gui/linien_gui/ui/modulation_sweep_panel.py
@@ -20,7 +20,7 @@
 from linien_gui.config import UI_PATH
 from linien_gui.ui.spin_box import CustomDoubleSpinBoxNoSign
 from linien_gui.utils import get_linien_app_instance, param2ui
-from PyQt5 import QtWidgets, uic
+from PyQt6 import QtWidgets, uic
 
 
 class ModulationAndSweepPanel(QtWidgets.QWidget):
diff --git a/linien-gui/linien_gui/ui/new_device_dialog.py b/linien-gui/linien_gui/ui/new_device_dialog.py
index 6a8cc977..eb3e84b7 100644
--- a/linien-gui/linien_gui/ui/new_device_dialog.py
+++ b/linien-gui/linien_gui/ui/new_device_dialog.py
@@ -20,7 +20,7 @@
 
 from linien_client.device import Device, add_device, update_device
 from linien_gui.config import UI_PATH
-from PyQt5 import QtWidgets, uic
+from PyQt6 import QtWidgets, uic
 
 
 class NewDeviceDialog(QtWidgets.QDialog):
diff --git a/linien-gui/linien_gui/ui/optimization_panel.py b/linien-gui/linien_gui/ui/optimization_panel.py
index 740927ed..cedc30b9 100644
--- a/linien-gui/linien_gui/ui/optimization_panel.py
+++ b/linien-gui/linien_gui/ui/optimization_panel.py
@@ -20,7 +20,7 @@
 from linien_gui.config import UI_PATH
 from linien_gui.ui.spin_box import CustomDoubleSpinBoxNoSign
 from linien_gui.utils import get_linien_app_instance, param2ui
-from PyQt5 import QtWidgets, uic
+from PyQt6 import QtWidgets, uic
 
 
 class OptimizationPanel(QtWidgets.QWidget):
diff --git a/linien-gui/linien_gui/ui/plot_widget.py b/linien-gui/linien_gui/ui/plot_widget.py
index ee7d7b16..2e34f0ed 100644
--- a/linien-gui/linien_gui/ui/plot_widget.py
+++ b/linien-gui/linien_gui/ui/plot_widget.py
@@ -34,8 +34,8 @@
 )
 from linien_gui.config import DEFAULT_PLOT_RATE_LIMIT, N_COLORS, Color
 from linien_gui.utils import get_linien_app_instance
-from PyQt5 import QtGui, QtWidgets
-from PyQt5.QtCore import pyqtSignal
+from PyQt6 import QtGui, QtWidgets
+from PyQt6.QtCore import pyqtSignal
 from pyqtgraph.Qt import QtCore
 
 # NOTE: this is required for using a pen_width > 1. There is a bug though that causes
diff --git a/linien-gui/linien_gui/ui/psd_table_widget.py b/linien-gui/linien_gui/ui/psd_table_widget.py
index 48d99eeb..2b490902 100644
--- a/linien-gui/linien_gui/ui/psd_table_widget.py
+++ b/linien-gui/linien_gui/ui/psd_table_widget.py
@@ -19,8 +19,8 @@
 from datetime import datetime
 
 from linien_gui.utils import color_to_hex, get_linien_app_instance
-from PyQt5 import QtCore, QtWidgets
-from PyQt5.QtCore import pyqtSignal
+from PyQt6 import QtCore, QtWidgets
+from PyQt6.QtCore import pyqtSignal
 
 
 class PSDTableWidget(QtWidgets.QTableWidget):
diff --git a/linien-gui/linien_gui/ui/psd_window.py b/linien-gui/linien_gui/ui/psd_window.py
index dea1dc7e..3110102a 100644
--- a/linien-gui/linien_gui/ui/psd_window.py
+++ b/linien-gui/linien_gui/ui/psd_window.py
@@ -29,7 +29,7 @@
     param2ui,
     set_window_icon,
 )
-from PyQt5 import QtWidgets, uic
+from PyQt6 import QtWidgets, uic
 
 
 class PSDWindow(QtWidgets.QMainWindow):
diff --git a/linien-gui/linien_gui/ui/right_panel.py b/linien-gui/linien_gui/ui/right_panel.py
index 4dc4f707..9fe7b85f 100644
--- a/linien-gui/linien_gui/ui/right_panel.py
+++ b/linien-gui/linien_gui/ui/right_panel.py
@@ -17,7 +17,7 @@
 # along with Linien.  If not, see <http://www.gnu.org/licenses/>.
 
 from linien_gui.utils import get_linien_app_instance
-from PyQt5 import QtCore, QtWidgets
+from PyQt6 import QtCore, QtWidgets
 
 
 class RightPanel(QtWidgets.QWidget):
diff --git a/linien-gui/linien_gui/ui/spectroscopy_panel.py b/linien-gui/linien_gui/ui/spectroscopy_panel.py
index b4c76aa3..475dcd98 100644
--- a/linien-gui/linien_gui/ui/spectroscopy_panel.py
+++ b/linien-gui/linien_gui/ui/spectroscopy_panel.py
@@ -23,7 +23,7 @@
 from linien_gui.config import UI_PATH
 from linien_gui.ui.spin_box import CustomDoubleSpinBox, CustomDoubleSpinBoxNoSign
 from linien_gui.utils import get_linien_app_instance, param2ui
-from PyQt5 import QtWidgets, uic
+from PyQt6 import QtWidgets, uic
 
 
 class SpectroscopyPanel(QtWidgets.QWidget):
@@ -36,8 +36,8 @@ class SpectroscopyPanel(QtWidgets.QWidget):
     manualFilterWidget: QtWidgets.QWidget
     signalOffsetSpinBox: CustomDoubleSpinBox
 
-    def __init__(self, *args):
-        super(SpectroscopyPanel, self).__init__(*args)
+    def __init__(self, *args, **kwargs):
+        super(SpectroscopyPanel, self).__init__(*args, **kwargs)
         uic.loadUi(UI_PATH / "spectroscopy_panel.ui", self)
         self.app = get_linien_app_instance()
         self.app.connection_established.connect(self.on_connection_established)
diff --git a/linien-gui/linien_gui/ui/spin_box.py b/linien-gui/linien_gui/ui/spin_box.py
index f2884d9a..52fba206 100644
--- a/linien-gui/linien_gui/ui/spin_box.py
+++ b/linien-gui/linien_gui/ui/spin_box.py
@@ -15,7 +15,7 @@
 # You should have received a copy of the GNU General Public License
 # along with Linien.  If not, see <http://www.gnu.org/licenses/>.
 
-from PyQt5.QtWidgets import QDoubleSpinBox, QSpinBox
+from PyQt6.QtWidgets import QDoubleSpinBox, QSpinBox
 
 
 class CustomDoubleSpinBox(QDoubleSpinBox):
diff --git a/linien-gui/linien_gui/ui/sweep_control.py b/linien-gui/linien_gui/ui/sweep_control.py
index 61f41122..cd9088a5 100644
--- a/linien-gui/linien_gui/ui/sweep_control.py
+++ b/linien-gui/linien_gui/ui/sweep_control.py
@@ -17,7 +17,7 @@
 
 import superqt
 from linien_gui.utils import get_linien_app_instance
-from PyQt5 import QtCore, QtWidgets
+from PyQt6 import QtCore, QtWidgets
 
 
 class SweepControlWidget(QtWidgets.QWidget):
diff --git a/linien-gui/linien_gui/ui/version_checker.py b/linien-gui/linien_gui/ui/version_checker.py
index fa4bfa7d..00f53c40 100644
--- a/linien-gui/linien_gui/ui/version_checker.py
+++ b/linien-gui/linien_gui/ui/version_checker.py
@@ -21,7 +21,7 @@
 import linien_gui
 import requests
 from packaging import version
-from PyQt5.QtCore import QThread, pyqtSignal
+from PyQt6.QtCore import QThread, pyqtSignal
 
 logger = logging.getLogger(__name__)
 logger.setLevel(logging.DEBUG)
diff --git a/linien-gui/linien_gui/ui/view_panel.py b/linien-gui/linien_gui/ui/view_panel.py
index d39d3857..d9ec31a9 100644
--- a/linien-gui/linien_gui/ui/view_panel.py
+++ b/linien-gui/linien_gui/ui/view_panel.py
@@ -24,7 +24,7 @@
 from linien_gui.config import N_COLORS, UI_PATH
 from linien_gui.ui.spin_box import CustomDoubleSpinBoxNoSign, CustomSpinBox
 from linien_gui.utils import color_to_hex, get_linien_app_instance, param2ui
-from PyQt5 import QtGui, QtWidgets, uic
+from PyQt6 import QtGui, QtWidgets, uic
 
 
 class ViewPanel(QtWidgets.QWidget):
diff --git a/linien-gui/linien_gui/utils.py b/linien-gui/linien_gui/utils.py
index 1e4bd360..1928850b 100644
--- a/linien-gui/linien_gui/utils.py
+++ b/linien-gui/linien_gui/utils.py
@@ -20,8 +20,8 @@
 from typing import TYPE_CHECKING, Any, Callable, Tuple
 
 from linien_client.remote_parameters import RemoteParameter
-from PyQt5 import QtWidgets
-from PyQt5.QtWidgets import (
+from PyQt6 import QtWidgets
+from PyQt6.QtWidgets import (
     QCheckBox,
     QComboBox,
     QDoubleSpinBox,
diff --git a/linien-gui/pkg.nix b/linien-gui/pkg.nix
index 9c1e8610..de020c18 100644
--- a/linien-gui/pkg.nix
+++ b/linien-gui/pkg.nix
@@ -5,11 +5,11 @@
 , setuptools
 , requests
 , pyqtgraph
-, pyqt5
+, pyqt6
 , superqt
 , click
 , linien-client
-, qt5
+, qt6
 , makeDesktopItem
 , copyDesktopItems
 , graphicsmagick
@@ -24,20 +24,20 @@ buildPythonPackage rec {
 
   nativeBuildInputs = [
     setuptools
-    qt5.wrapQtAppsHook
+    qt6.wrapQtAppsHook
     copyDesktopItems
     graphicsmagick
   ];
 
   buildInputs = [
-    qt5.qtbase
-    qt5.qtwayland
+    qt6.qtbase
+    qt6.qtwayland
   ];
 
   propagatedBuildInputs = [
     requests
     pyqtgraph
-    pyqt5
+    pyqt6
     superqt
     click
     linien-client
diff --git a/linien-gui/pyinstaller.spec b/linien-gui/pyinstaller.spec
index 6f12fb9a..941ce32c 100644
--- a/linien-gui/pyinstaller.spec
+++ b/linien-gui/pyinstaller.spec
@@ -11,7 +11,7 @@ a = Analysis(
     pathex=[],
     binaries=[],
     datas=datas,
-    hiddenimports=["PyQt5.sip", "superqt", "scipy.special._cdflib"],
+    hiddenimports=["PyQt6.sip", "superqt", "scipy.special._cdflib"],
     hookspath=[],
     runtime_hooks=[],
     excludes=[],
diff --git a/linien-gui/pyproject.toml b/linien-gui/pyproject.toml
index f93b0e8b..bced3b5b 100644
--- a/linien-gui/pyproject.toml
+++ b/linien-gui/pyproject.toml
@@ -25,7 +25,7 @@ requires-python = ">=3.8"
 dependencies = [
     "click>=8.1.7,<9.0",
     "pyqtgraph>=0.10.0",
-    "PyQt5>=5.12.0,<6.0",
+    "PyQt6<7.0",
     "requests>=2.31.0,<3.0",
     "superqt>=0.2.3",
     "linien_client==2.0.4",