Peter Gordon MacKay is a Canadian lawyer and politician. He was a Member of Parliament from 1997 to 2015 and has served as Minister of Justice and Attorney General (2013–2015), Minister of National Defence (2007–2013), and Minister of Foreign Affairs (2006–2007) in the Cabinet of Canada under Prime Minister Stephen Harper. MacKay was the final leader of the Progressive Conservative Party of Canada, and he agreed to merge the party with Stephen Harper's Canadian Alliance in 2003, forming the Conservative Party of Canada and making MacKay one of the co-founders of the current conservative wing of Canadian politics.

The minister of justice and attorney general of Canada is a dual-role portfolio in the Canadian Cabinet.