To promote and protect open source...

As a global non-profit, The Open Source Initiative (OSI) protects and promotes open source software, development and communities, championing software freedom in society through education, collaboration, and infrastructure, stewarding the Open Source Definition (OSD), and preventing abuse of the ideals and ethos inherent to the open source movement. See our about and history pages for more.

Open source software is software that can be freely used, changed, and shared (in modified or unmodified form) by anyone. Open source software is made by many people, and distributed under licenses that comply with the Open Source Definition.


Open Source Initiative Announces New Partnership With Adblock Plus

PALO ALTO, Calif. - Jan. 16, 2018 -- Adblock Plus, the most popular Internet ad blocker today, joins The Open Source Initiative® (OSI) as corporate sponsors. Since its very first version, Adblock Plus has been an open source project that has developed into a successful business with over 100 million users worldwide. As such, the German company behind it, eyeo GmbH, has decided it is time to give back to the open source community.

Twenty Years and Counting

The third decade of open source software starts in February 2018. How did it rise to dominance, and what’s next?

20 years ago, in February 1998, the term “open source” was first applied to software, Soon afterwards, the Open Source Definition was created and the seeds that became the Open Source Initiative (OSI) were sown. As the OSD’s author Bruce Perens relates,