Elmer MacIntosh MacKay, PC, QC (born August 5, 1936) is a retired Canadian politician.

MacKay was born in Hopewell, Nova Scotia. He was first elected to the Canadian House of Commons as the Progressive Conservative (PC) Member of Parliament (MP) for Central Nova through a 1971 by-election. He was re-elected in subsequent elections, and served as Minister of Regional Economic Expansion in the short lived (1979–1980) government of Prime Minister Joe Clark.

MacKay resigned his parliamentary seat in 1983 in order to allow newly elected PC leader Brian Mulroney to enter Parliament through a by-election in MacKay's Nova Scotia riding. In the subsequent 1984 election, Mulroney moved to a Quebec riding, and MacKay was again returned to the House as Central Nova's MP.

Following the election, Mulroney became prime minister, and appointed MacKay to the Canadian Cabinet where he served as Solicitor General of Canada for a year before becoming Minister of National Revenue. In 1989, MacKay became Minister of Public Works. From 1989 to 1991, he was also responsible for the Atlantic Canada Opportunities Agency Act. The opposition Liberals and New Democratic Party often accused MacKay of doling out patronage appointments. While no wrongdoing was ever proven, MacKay was removed from the ACOA portfolio in 1991. From 1991 to 1993, he remained Public Works minister and was given responsibility for the Canada Mortgage and Housing Corporation.

Peter Gordon MacKay, PC, QC, MP (born September 27, 1965) is a lawyer and politician from Nova Scotia, Canada. He is the Member of Parliament for Central Nova and currently serves as Minister of National Defence in the Cabinet of Canada. He is married to Nazanin Afshin-Jam an Iranian-Canadian model, singer, and human rights activist, and a former Miss World Canada.

MacKay was the final leader of the Progressive Conservative Party of Canada (PC Party). On October 15, 2003, he and Canadian Alliance leader Stephen Harper agreed to merge the two parties, forming the Conservative Party of Canada. In December 2003, members of both parties ratified the merger.

MacKay was born in New Glasgow, Nova Scotia. His father, Elmer MacKay, is a former PC cabinet minister, lumber businessman, and lawyer. His mother, Macha MacKay (née Delap), is a psychologist and peace activist; through her, MacKay is descended from James Alexander, 3rd Earl of Caledon and James Grimston, 1st Earl of Verulam. MacKay grew up in Wolfville, Nova Scotia with his three siblings. He graduated from Horton District High School in Greenwich, Nova Scotia, and then went on to graduate with a Bachelor of Arts degree from Acadia University/Carleton University in 1987, MacKay then studied Law at Dalhousie University and was called to the Nova Scotia Bar in June 1991. He worked for Thyssen Henschel, steel producer, in Halifax, Nova Scotia, and in Düsseldorf and Kassel, Germany.