Douglas Grinslade Lewis, PC KC (born April 17, 1938) is a Canadian accountant, lawyer and former politician.
A chartered accountant and lawyer by training, Lewis entered the House of Commons of Canada when he won the seat of Simcoe North, Ontario, as a Progressive Conservative in the 1979 federal election.
With the victory of the Progressive Conservatives under Brian Mulroney in the 1984 general election, Lewis again became a parliamentary secretary.
At the end of 1988, he became Acting President of the Treasury Board, and, a month later in January 1989, he was named Minister of Justice.
In July 2000, however, he insisted to reporters that he was a loyal supporter of Joe Clark's renewed leadership of the Progressive Conservative party.