PyQt is a Python binding of the cross-platform GUI toolkit Qt, implemented as a Python plug-in. PyQt is free software developed by the British firm Riverbank Computing. It is available under similar terms to Qt versions older than 4.5; this means a variety of licenses including GNU General Public License (GPL) and commercial license, but not the GNU Lesser General Public License (LGPL). PyQt supports Microsoft Windows as well as various kinds of UNIX, including Linux and macOS.

PyQt implements around 440 classes and over 6,000 functions and methods including:

To automatically generate these bindings, Phil Thompson developed the tool SIP, which is also used in other projects.

PyQt was first released by Riverbank Computing in 1998.

In August 2009, Nokia sought for the Python binding to be available under the LGPL license. At the time, Nokia owned Qt Software, the developer of QT. After failing to reach an agreement with Riverbank Computing, Nokia released its binding, PySide, providing similar functionality.

PyQt4 contains the following Python modules.

PyQt5 contains the following Python modules:

PyQt version 4 works with both Qt 4 and Qt 5. PyQt version 5 only supports Qt version 5, and drops support for features that are deprecated in Qt 5.