Allan Joseph MacEachen PC OC (/məˈkɛkən/; July 6, 1921 – September 12, 2017) was a Canadian politician and statesman who served as a senator and several times as a Cabinet minister.

Born in Inverness on Nova Scotia's Cape Breton Island, MacEachen graduated from St. Francis Xavier University, and lectured in economics for several years at the school.

It was the beginning of a lengthy career in cabinet in which MacEachen served in several portfolios under Prime Ministers Pearson, Pierre Trudeau and John Turner.

Over the course of his career, MacEachen held the following portfolios: Labour, National Health and Welfare, Manpower and Immigration, Privy Council, External Affairs, and Finance.

In his memoirs, published in 1993, Trudeau wrote that MacEachen "had a very good strategic sense, both in and out of Parliament, and he lived and breathed politics."

In 1979, when the Liberals lost the election to Joe Clark's Conservatives, MacEachen served as interim Leader of the Opposition when Trudeau announced his retirement from politics.

In 1988, after a request by Turner, MacEachen blocked the Canada-U.S. Free Trade Agreement in the Senate to force an election before the issue was settled.

MacEachen then led a filibuster against the bill, with Liberal members defying Speaker Guy Charbonneau, who voted for Conservative motions.

After leaving the Senate, MacEachen retired to Nova Scotia spending the rest of his life at his house on Lake Ainslie in Inverness County, Cape Breton and in Antigonish.