The Honourable Douglas Grnslade (Doug) Lewis (born April 17 1938) is a former Canadian politician.

A chartered accountant and lawyer by training, Lewis entered the Canadian House of Commons when he won the seat of Simcoe North, Ontario as a Progressive Conservative in the 1979 federal election. In the short-lived Joe Clark government he was Parliamentary Secretary to the Minister of Supply and Service .

Re-elected in the 1980 federal election that returned the Liberals to power, Lewis moved to the opposition benches serving first as Deputy House Leader from 1981 to February 1983 and then as Official Opposition House Leader until September 1983.

With the victory of the Progressive Conservatives under Brian Mulroney in the 1984 general election, Lewis again became a parliamentary secretary until 1987 when he entered the Cabinet as both Minsiter of State to the Government House Leader and Minister of State (Treasury Board). At the end of 1988 he became Acting President of the Treasury Board and a month later, in January 1989 he was promoted to Minister of Justice. He also served as Government House Leader from April 1989 to February 1990.

In April 1990, Lewis was moved from Justice to the position of Minister of Transport and in 1991 he was moved again, this time to the position of Solicitor General of Canada.

When Kim Campbell succeeded Mulroney as Prime Minister of Canada in June 1993 she kept Lewis in Cabinet as Solicitor General while also making him Government House Leader. Both Lewis and the Campbell government were defeated in the fall 1993 general election. Following his political defeat, he returned to his law practice.

Lewis remained a supporter of the Progressive Conservatives through the 1990s. However, in 2000 he supported Tom Long's candidacy to lead the new Canadian Alliance. In July 2000, however, he inisted to reporters that he was a loyal supporter of Joe Clark's renewed leadership of the Progressive Conservative party.