At the time of writing in 2013, this was one way to do it. Composer has added support for better ways: See @igorw 's answer
DO YOU HAVE A REPOSITORY?
Git, Mercurial, and SVN is supported by Composer.
DO YOU HAVE WRITE ACCESS TO THE REPOSITORY?
Yes?
DOES THE REPOSITORY HAVE A composer.json FILE
If you have a repository you can write to: Add a composer.json file, or fix the existing one, and DON'T use the solution below.
Go to @igorw 's answer
ONLY USE THIS IF YOU DON'T HAVE A REPOSITORY
OR IF THE REPOSITORY DOES NOT HAVE A composer.json AND YOU CANNOT ADD IT
This will override everything that Composer may be able to read from the original repository's composer.json, including the dependencies of the package and the autoloading.
Using the package type will transfer the burden of correctly defining everything onto you. The easier way is to have a composer.json file in the repository, and just use it.
This solution really only is for the rare cases where you have an abandoned ZIP download that you cannot alter, or a repository you can only read, but it isn't maintained anymore.
"repositories": [ { "type":"package", "package": { "name": "l3pp4rd/doctrine-extensions", "version":"master", "source": { "url": "https://github.com/l3pp4rd/DoctrineExtensions.git", "type": "git", "reference":"master" } } } ], "require": { "l3pp4rd/doctrine-extensions": "master" } 
