Erik Hersholt Nielsen, P.C., D.F.C., Q.C., LL.B., (born February 24 1924) is a former Canadian politician and longtime Progressive Conservative Member of Parliament for Yukon.

Born in Regina, Saskatchewan, he was Minister of Public Works in the short-lived government of Joe Clark. After the Tories were defeated in the 1980 Canadian election he served as Opposition House Leader from 1981 until 1983 and engineered the Bell Ringing Affair to protest the Liberal government's omnibus energy bill. The business of the Canadian House of Commons ground to a halt for three weeks because the Opposition refused to respond to the bell summoning Members of Parliament to come to the chamber to vote. Nielsen served as Acting Leader of the Opposition in 1983 between the resignation of Joe Clark and the election of Brian Mulroney, and continued to lead the party in the House until Mulroney won a seat in a by-election at which point Nielsen returned to his previous position as House Leader.

When Mulroney became Prime Minister of Canada he made Nielson his deputy prime minister from 1984 to 1986 and President of the Queen's Privy Council for Canada from 1984 to 1985 (effectively making him the senior Government House Leader in all but name). He also served as Minister of National Defence from 1985 to 1986. The tenaciousness and aggressiveness that made Nielsen a successful Opposition MP made him a liability as a Cabinet minister as he gave the impression of being secretive and disdainful of criticism by the Opposition and the media. His habit of stonewalling questions had the effect of prolonging the shelf life of political scandals in Parliament and thus hurt the government's reputation. He was dropped from Cabinet in June 1986 and resigned his seat in Parliament in January 1987 when he was given the position of chairman of the National Transportation Agency. He withdrew from the public service in 1992 to become president of Solar Engineering, Hawaii Inc. and Solar Electric Engineering Distributors Canada.

Nielsen is also the brother of actor Leslie Nielsen. The relationship informed the premise of an HBO spoof documentary titled The Canadian Conspiracy, comically alleging a Canadian subversion of the United States through its media.

Known for a tight-lipped reticence during his time in office, he wrote a volume of memoirs, The House Is Not a Home (1989, ISBN 0771594267), noted for its bracing directness both about his colleagues and about his own personal life.

|- style="text-align: center;" | width="30%" |Preceded by:
Joe Clark | width="40%" style="text-align: center;" |Leader of the Opposition in the House of Commons
1983 | width="30%" |Succeeded by:
Brian Mulroney

|- style="text-align: center;" | width="30%" |Preceded by:
Joe Clark | width="40%" style="text-align: center;" |Progressive Conservative Leader
1983 | width="30%" |Succeeded by:
Brian Mulroney

|- style="text-align: center;" | width="30%" |Preceded by:
James Aubrey Simmons | width="40%" style="text-align: center;" |Member of Parliament for Yukon
1957-1987 | width="30%" |Succeeded by:
Audrey McLaughlin