I am contributing to a library that is licensed under the MIT license.

In the license and in each class file it has a comment at the top saying:

Copyright (c) 2011 Joe Bloggs <[email protected]>

I assume that he owns the copyright to the file, and can change the license of that file as he sees fit.

If I contribute to the library with a new class entirely write by me, can I claim copyright of that file. And put:

Copyright (c) 2011 Petah Piper <[email protected]>

at the top?


2 Answers 2


I'm not a lawyer, but the answer is yes. Copyright holder is the person or entity that can claim right to having created a piece work, or to whom such right has been transferred. The MIT license is not about transferring copyright, but about granting legal right to use the (copyrighted) work as stated in the license. If you write a class, you have the copyright to it, even if its actual use depends on third-party work.

Once you add your class to the software package and distribute the whole package, the package has multiple copyright holders: the original authors, and you. You are allowed to distribute the parts from the original package because the MIT license allows you to "use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software".

  • 1
    AFAIK, you should also automatically hold the copyright - the notice is just so you can enforce it easier.
    – Pubby
    Nov 2, 2011 at 21:34
  • 2
    Yes, copyright is created by being the author of a work, not by claiming it. Even if there's no copyright marking you are still the holder of the copyright, but there's no point in leaving it out. Nov 2, 2011 at 21:40
  • Do note that some projects require that copyrights for modifications be legally assigned to the project maintainer, so that the project can more easily modify the project's licensing terms at a later date (this issue bit a lot of GPL projects when GPLv3 was unveiled, for example). You should verify with the project maintainer about whether there are any such requirements with the particular project to which you're contributing. Nov 2, 2011 at 21:45
  • Yes, but if the source code is distributed under MIT license, you can always create your own derivative of the project. That's different and separate from committing code back to the original project's source code repository; that might require (and usually does) a copyright transfer. Nov 2, 2011 at 21:59
  • @Trevor Powell: That's a project decision applying to their main source branch only. You are always free to develop private branches (forks). See MySQL/MariaDB : the latter is a fork with copyrights not assigned to Oracle.
    – MSalters
    Nov 3, 2011 at 12:47

Yes, you can.

I assume that he owns the copyright to the file, and can change the license of that file as he sees fit.

He cannot change the terms of existing licenses nor can he prevent new licensees from being issued (by others, but to his code) under different terms. The MIT license is irrevocable and includes automatic issuing of licenses to new recipients.

  • 6
    A legal fine point: The MIT license is irrevocable for people who have already received a specific distribution of the work. That is, I can't give them the work and then say "ha ha, it's commercial now, you have to pay me to use something that was free before". But the copyright owner DOES have the right to stop distributing under the MIT license whenever they like (though everyone who has already received the work under that license is still entitled to use it or re-distribute it under that license), and to distribute it (or work based on it) to new consumers under some different license. Nov 3, 2011 at 6:11
  • A finer point: It takes a lawyer to interpret MIT. As a result, if little expertise went into the application of the MIT license with a work—especially if pushed by a centralized authority—the terms of the MIT may not be as irrevocable as one might think. That's how law really works.
    – vhs
    Mar 24, 2019 at 12:23

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