ACORN International is a federation of autonomous member-based community organizations and tenants unions. The organisations represent a total global membership of approximately 250,000 members.

ACORN International has active affiliated organisations in multiple countries, such as Cameroon, Canada, the Czech Republic, England, France, Honduras, India, Ireland, Italy, Kenya, Peru, Scotland, Tunisia, the United States, and Wales.

Acorn International was created in 2004 by members and staff of the Association of Community Organizations for Reform Now (ACORN). The Founder and Chief Organizer is Wade Rathke. The headquarters of ACORN International are in New Orleans and Toronto. Much of the capacity outside of the organizing areas is provided by interns and volunteers that have come from George Brown College (Toronto), Carleton University (Ottawa), York University (Toronto), Georgia State University, the University of Edinburgh (Scotland), and many others.

Since its creation it has focused on a wide variety of local campaigns and initiatives, including fighting for potable water, paved roads, schools and parks in San Juan Laragancho in Lima, Peru, working to organize ragpickers and hawkers in India's mega-slums, and working to raise the standards for tenants in cities across Canada. Much of ACORN International's work in Latin America, Africa and India focuses on mega-slums like Dharavi (Mumbai), San Juan Laragancho (Lima), La Matanza (Buenos Aires), Korogocho (Nairobi), the ITO community (Delhi), Col. Ramon Amalia Amador (Tegucigalpa), and Choloma (San Pedro Sula) among others.

ACORN International's major projects have included the Commonwealth Games campaign. and the Remittance Justice campaign.

ACORN International conducts research on topics relevant to its members' campaigns. Recent topics have included rural electrical cooperative governance, voter purges, and hospital accessibility and accountability. Research is conducted in partnership with the Labor Neighbor Research and Training Center and United Labor Unions.

Previously, the organization researched the interest rates, transparency, and role (if any) of micro-finance in poverty reduction. A white paper, along the lines of those developed for the Remittance Justice Campaign, entitled "Mega Troubles for Micro-Finance" was released in the summer of 2011 demanding among other things that no additional donor or government money be invested in micro-finance since it has failed to reduce poverty according to both ACORN International's research and research done by the Abdul Latif Jameel Poverty Action Lab. Responses received from a number of international development agencies such as the World Bank and UK AID have been in agreement with many of the criticisms of microfinance industries included in the report, but do not agree with the report's final recommendations of eliminating all public funding of microfinance among other suggestions.

The first ACORN branch in the UK opened in Bristol in 2014 by three people – all three of whom had experience organising the Bristol Industrial Workers of the World, two of them also graduates of the Community Organisers programme. Part of the funding to establish ACORN in the UK came from the Big Society initiative. Initially ACORN was not set up to focus much on housing issues, with this focus developing as repeated concerns regarding housing were raised.