Peter Andrew Stewart Milliken PC OC FRSC UE (born November 12, 1946) is a Canadian lawyer and politician.

His legacy includes his landmark rulings on Parliament's right to information, which are key elements of parliamentary precedent both in Canada and throughout the Commonwealth.

He is the cousin of John Matheson, a former Liberal Member of Parliament (MP) best known for his prominent role in adopting the red maple leaf as the Flag of Canada.

[7] Called to the Ontario Bar in 1973, Milliken was a partner at the prestigious Kingston law firm, Cunningham, Swan, Carty, Little & Bonham, before entering political life.

He also lectured on a part-time basis at the Queen's University School of Business from 1973 to 1981, became a governor of the Kingston General Hospital in 1977, and has been a trustee with the Chalmers United Church.

A fan of classical music, he has sung with the Pro Arte Singers and the Chalmers United Church Choir as well as serving on the board of the Kingston Symphony.

Milliken has long been active in political matters, having served as president of the Frontenac Addington Provincial Liberal Association Kingston in the 1980s.

He subscribed to the Canadian House of Commons Hansard at age sixteen, and once wrote a thesis paper on Question Period.

[12] Milliken won the Kingston and the Islands Liberal nomination in 1988 over local alderman Alex Lampropoulos,[13] and defeated well-known Progressive Conservative cabinet minister Flora MacDonald by 2,712 votes in the 1988 general election.

[18] In the same year, Milliken and fellow Liberal MP John Godfrey introduced the Godfrey-Milliken Bill as a satirical response to the American Helms-Burton Act.

[20] Godfrey and Milliken gave a twenty-minute presentation on their bill in Washington, D.C. in early 1997, and were greeted with warm applause from local Helms-Burton opponents.

Though his party was no longer in government, he was re-elected Speaker of the House for the 39th Parliament on April 3, 2006, defeating fellow Liberals Diane Marleau and Marcel Proulx on the first ballot.

[28] With his re-election, he became only the second Speaker chosen from an opposition party in the history of the House of Commons (James Jerome, Liberal Member of Parliament for the Sudbury riding during the Joe Clark government, being the other).

[1] On March 18, 2010, the three opposition parties asked Milliken to make a pivotal ruling on a question of privilege (specifically the power to send for persons, papers and records), in regards to Parliament's request for documents on the transfer of Afghan detainees, a notable issue in 2009 and 2010.

[38][39] On March 9, 2011, Milliken made two historic rulings finding a prima facie case of contempt of Parliament against the government of Stephen Harper,[40] referring the matter to the Procedure Committee.