Alliance Atlantis Communications Inc. (formerly traded as TSX:AAC) was a Montreal and Toronto-based media company, which operated primarily as a specialty service operator in Canada. Alliance Atlantis also had offices in Toronto, Halifax, Los Angeles, London, Dublin, Madrid, Barcelona, Shannon and Sydney.

Alliance Atlantis was acquired by CanWest Global Communications and an affiliate of Goldman Sachs in 2007. The movie business now operates independently as Alliance Films, and the international television distribution businesses is now owned by Goldman Sachs.

All of the former Alliance Atlantis specialty networks are now owned by Canwest.

The company was formed in 1998 from the merger of two former production companies, Alliance Communications and Atlantis Communications. The merger was a bit unusual in that the head of Atlantis, Michael MacMillan, became CEO of the new firm even though Atlantis was the smaller partner in the transaction ; Alliance's CEO, Robert Lantos, was specifically interested in moving back into a production role . (The merger was also parodied on Made in Canada, when that show's Pyramid Productions merged with a company called Prodigy.)

At the time of the merger, both companies had launched various Canadian specialty television services; in 1995, Alliance launched Showcase Television while Atlantis launched Life Network (which has since been renamed "Slice"); in fall 1997 the companies launched History Television and HGTV Canada respectively. Atlantis had also been a major investor in YTV in its first few years before selling out to what is now Corus Entertainment.

Alliance Atlantis has been known to fund projects regarded as too controversial by US companies, such as Bowling for Columbine; it was the Canadian distributor of Fahrenheit 9/11.blank">http://www.cbc.ca/story/arts/national/2004/06/09/Arts/moorecda040609.html In 2003, the company purchased _Salter Street Films, which produced a number of television shows for both the Canadian and international market. However, soon after the acquisition, Salter Street was disbanded and its active projects were transferred to Alliance Atlantis' own television production/development division.

Citing lower profits, it has all but closed its production arm, aside from the highly-profitable CSI: Crime Scene Investigation family of series, which it co-produces with CBS Paramount Television. It briefly maintained Salter Street's long-running This Hour Has 22 Minutes before transferring the show to the Halifax Film Company, made up of former Salter Street employees.

Its primary business is now through its ownership of a number of Canadian specialty services, which, in addition to those listed above, now include Food Network, Discovery Health, BBC Canada, BBC Kids and more.

In 2007, Alliance Atlantis was named one of Canada's Top 100 Employers, as published in Maclean's magazine, the only broadcaster to be included on the list.