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

MacKay was first elected to the Canadian House of Commons as the Progressive Conservative MP for Central Nova through a 1971 by-election. He was re-elected in subsequent votes and served as Minister of Regional Economic Expansion in the short lived (1979-1980) government of Joe Clark.

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

Mulroney became the new Prime Minister of Canada 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. While the parliamentary opposition often accused MacKay of doling out patronage no wrongdoing was ever proven, however he lost the ACOA portfolio in 1991. From 1991 to 1993 he remained Public Works minister and was also given responsibility for the Canada Mortgage and Housing Corporation.

MacKay retired from Cabinet when Mulroney's tenure as party leader ended 1993 and did not run in the 1993 Canadian election.

After leaving politics MacKay's name was mentioned in relation to the Airbus affair due to his friendship with principal figures such as Karlheinz Schreiber and Frank Moores but no specific allegations were ever made against MacKay.

Elmer MacKay's son, Peter MacKay, entered politics several years after his father's retirement and was the final leader of the Progressive Conservative Party of Canada.