Greenstone is a suite of software for building and distributing digital library collections. It provides a new way of organizing information and publishing it on the Internet or on CD-ROM. Greenstone is produced by the New Zealand Digital Library Project at the University of Waikato, and developed and distributed in cooperation with UNESCO and the Human Info NGO.

Greenstone is open-source, multilingual software, issued under the terms of the GNU General Public License, which aims to empower users, particularly in universities, libraries, and other public service institutions, to build their own digital libraries. Digital libraries are radically reforming how information is disseminated and acquired in UNESCO's partner communities and institutions in the fields of education, science and culture around the world, and particularly in developing countries. It is hoped that this software will encourage the effective deployment of digital libraries to share information and place it in the public domain.

The complete Greenstone interface, and all documentation, is available in English, French, Spanish, Russian and Kazakh. Greenstone also has interfaces in many other languages.