Atheist Alliance International (AAI) is a non-profit advocacy organization committed to raising awareness and educating the public about atheism. The group supports atheist and freethought organizations around the world through promoting local campaigns, raising awareness of related issues, sponsoring secular education projects, and facilitating interaction among secular groups and individuals.

Atheist Alliance International is an off-shoot of the Atheist Alliance.

Atheist Alliance was established in 1991 and incorporated in August 1992. Originally an alliance of four U.S.-based local atheist groups, it grew throughout the United States and internationally, and in 2001 it changed its name to Atheist Alliance International (AAI).

In 2006 AAI held its first international conference in Reykjavík, Iceland in coordination with the Atheist Society of Iceland.

In 2010 and 2011, AAI members approved the strategic separation of its international and U.S. segments:

The launch of the newly restructured AAI occurred at the World Atheist Convention in Dublin, Ireland on 3 June 2011. AAI then described the organisation as follows:

Atheist Alliance International (AAI) is a global network of atheist and freethought groups and individuals, committed to educating its members and the public about atheism, secularism and related issues.

A positive global voice for atheism and secularism, AAl: