Invenio - Invenio is a free, open-source software to run a digital library or document repository on the web.
Greenstone Digital Library - Greenstone is a suite of software tools for building and distributing digital library collections...
Koha - Koha is the first free and open source software library automation package (ILS).
Evergreen ILS - Evergreen - Open Source Library Software
Atoll Digital Library - Atoll Digital Library is an open source platform for building digital library collections.
TinyCat - The online catalog and integrated library system for tiny libraries, powered by LibraryThing.