Ask Ubuntu is a question and answer site for Ubuntu users and developers. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

What is the relationship between Ubuntu and QT and Canonical? The coming Ubuntu phone looks interesting. Ubuntu seems to be interwoven with QT. If my company wants to write commercial C++ apps calling QT (or Ubuntu) libraries that my company has not modified, then I do NOT have to provide my company created source code with the app, correct? Thanks!

share|improve this question

Well, Qt is owned by Digia, not related to Ubuntu/Canonical.

Qt itself is licensed under the GNU Lesser General Public License (LGPL) version 2.1. This allows you to create and redistribute your closed source apps very well, as long as you're dynamically linking to Qt, or adhere to the limitations of statically linking.

See also these Q&A on SO:

While your question is specifically about Qt, keep in mind that in case you are using other libraries in addition to it you will need to check the terms on those as well. Another library may require you to release the source, but Qt does not.

share|improve this answer

Qt is available in 3 diffrent licenses:

  1. GPL: Suitable for open source programs, because you should release source code of your app.

  2. LGPL: Suitable for both open source and closed source programs. You need not release source code of your app. But if you created some changes in the qt library, you should release modified sourcecode.

  3. Commercial license: Suitable for closed source programs, You can make any change in qt libs and kept it as secret, and you can use any license for your app. But you should purchase license from Digia

In most of the cases LGPL license is enough. If your app's source code is very critical contact a lawyer before choosing the license.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.