Starting with version 1.7, Wintermute Engine is distributed as donationware, meaning that it is completely free to use for both commercial and non-commercial purposes, but if the users find it useful, they are encouraged to make a donation to support its further development.

Starting with version 1.8.9, source code of the engine and some of the supporting tools has been released under the LGPL license.

The source code of the portable Wintermute Lite 2D engine has been released under an MIT License and is hosted on a Bitbucket repository.

[1] While the Wintermute Lite engine is free of charge also for commercial use, licensing of the included BASS sound library is required.

[5] ScummVM integrated the WME lite engine into their framework as part of GSoC 2012 and 2013 student works.