Qt can run in Linux, Windows, and MacOS platforms, as well as embedded and mobile platforms such as Embedded Linux, Windows Embedded, Windows Mobile, Nokia Symbian, and Nokia N9/N900 smartphones. It is most notably used in Autodesk Maya, The Foundry's Nuke, Adobe Photoshop Elements, Skype, and VLC media player. It is also used by European Space Agency, DreamWorks, Google, HP, LucasFilm, Panasonics, Philips, Samsung, Siemens, Volvo, and more.

Distributed under the terms of the GNU Lesser General Public License (among others), Qt is free and open source software. It supports many compilers including GCC C++ compiler and Visual Studio. In addition, it has supports for internationalisation, SQL database access, XML parsing, multi-threading, and  networking. It can work with powerful open-source visualisation tools such as OpenGL and VTK. It also comes with wrapper for Python.

Qt is successful because programmers like it. For one thing, Qt makes sense. And for another, Qt is fun. Qt lets you concentrate on your tasks. When Qt's original artchitects faced a problem, they didn't just look for a good solution, or a quick solution, or the simplest solution. They looked for the right solution, and then they documented it. --- Matthias Ettrich, Foreword to C++ GUI Programming with Qt 4, 2nd Edition