PyQt5 Qt5 Runtime Libraries

5.15.18 · active · verified Fri Apr 10

The `pyqt5-qt5` package bundles a critical subset of the Qt installation required by PyQt5, enabling PyQt5 applications to run without a separate, system-wide Qt installation. It functions primarily as an internal dependency and is typically installed automatically by `pip` when the `PyQt5` package is installed. This package is licensed under the LGPL v3. As of its latest release, the current version is 5.15.18.

Warnings

gotcha `pyqt5-qt5` is an internal dependency containing Qt binaries, not Python modules for direct user import. Attempting to `import pyqt5_qt5` will result in an `ImportError` or unexpected behavior.
Fix: Do not import `pyqt5-qt5` directly. All user-facing code should import from `PyQt5` (e.g., `from PyQt5.QtWidgets import QApplication`).
gotcha It is highly recommended to install `PyQt5` directly (e.g., `pip install PyQt5`). This will automatically pull in the compatible version of `pyqt5-qt5`. Manually installing `pyqt5-qt5` or installing an incompatible version can lead to runtime errors or crashes.
Fix: Always install `PyQt5` as the primary package; let `pip` manage `pyqt5-qt5` as its dependency.
gotcha The `pyqt5-qt5` package contains the bundled Qt libraries, making its installation size significant (tens of megabytes to over a hundred, depending on platform and version). This is expected but can impact CI/CD pipelines or environments with limited disk space.
Fix: Be aware of the package size during installation. Consider using virtual environments to isolate dependencies.
deprecated `PyQt5` (and thus `pyqt5-qt5`) is based on Qt 5. For new projects or to leverage the latest Qt features, consider using `PyQt6` (which uses Qt 6 and has its own `pyqt6-qt6` dependency). While much of the `PyQt5` API is similar to `PyQt6`, there are some notable changes in `PyQt6` (e.g., fully qualified enums, `exec()` instead of `exec_()`).
Fix: For new development, evaluate `PyQt6`. If migrating from `PyQt5` to `PyQt6`, refer to migration guides for syntax adjustments.

Install

pip install pyqt5-qt5 Primary Installation (usually implicit via PyQt5)
pip install PyQt5 Recommended (installs pyqt5-qt5 automatically)

Quickstart

The `pyqt5-qt5` package is not directly imported or used by end-user code. Instead, it provides the underlying Qt binaries for `PyQt5`. The quickstart below demonstrates a basic 'Hello World' application using `PyQt5`, which relies on `pyqt5-qt5` for its runtime environment.

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QLabel
from PyQt5.QtGui import QIcon

if __name__ == '__main__':
    app = QApplication(sys.argv)
    
    window = QWidget()
    window.setWindowTitle('PyQt5 Hello World')
    window.setGeometry(100, 100, 400, 200)

    label = QLabel('Hello from PyQt5!', window)
    label.move(150, 80)
    
    window.show()
    sys.exit(app.exec_())

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