Dwight Duncan (born January 3, 1959 in Windsor, Ontario) is a politician in Ontario, Canada. He is currently a member of the Legislative Assembly of Ontario, and a Minister in Premier Dalton McGuinty's provincial Cabinet.

Duncan was educated at the University of Windsor and McGill University, receiving an MBA degree from the latter. He has been a member of the Ontario Liberal Party for several years, having served as Vice-Chair of its Social Development Committee as early as 1985. Duncan was elected to the Windsor City Council in 1988, and was re-elected in 1991. He also served as a Legislative Assistant to Ontario Minister of Labour Bill Wrye , was a Constituency Assistant to federal MP Herb Gray, and served as administrator of the Brentwood Recovery Home.

Duncan was first elected to the Ontario legislature in the provincial election of 1995, defeating New Democratic Party incumbent Wayne Lessard by 380 votes in the riding of Windsor-Walkerville . The provincial election was won by the Progressive Conservative Party of Ontario, and Duncan became a member of the official opposition, where he held a number of successive critic positions.

Duncan was a candidate for the leadership of the Ontario Liberal Party in late 1996, following the resignation of Lyn McLeod. He finished third on the first and second ballots, but was overtaken by Dalton McGuinty on the third and dropped from the race. He subsequently endorsed Gerard Kennedy, who lost to McGuinty on the fifth ballot. (At the announcement of McGuinty's victory, a TV Ontario camera recorded Duncan telling supporters, "we're f___ed".) See: Ontario Liberal Leadership Conventions.

Duncan's opponent from 1995, Wayne Lessard, won a by-election for another Windsor riding in 1997; in the provincial election of 1999, redistribution caused the two candidates to face each other again in the riding of Windsor-St. Clair . Duncan was again victorious, this time by over 4000 votes. The Progressive Conservatives won another majority government in the election, and Duncan remained in opposition. He became Liberal House Leader in June 1999, and became known for raising several technical points against the government in the legislature.

The Liberals won a majority in the provincial election of 2003, and Duncan was easily re-elected over NDP candidate Madeline Crnec . On October 23, 2003, he was appointed Ontario Minister of Energy , thereby becoming responsible for the difficult task of managing Ontario Power Generation.

On August 9, 2004 he said "I can't protect consumers from the fact that natural gas is running out" while speaking to the media about the hearings for Bill 100, Ontario Electricty restructuring act . Nevertheless, during the same month Duncan made trips to Alberta in an attempt to encourage companies to open natural gas electrical generating stations in Ontario.

Duncan is also government House Leader and Chair of Caucus. In late 2003, he was a leading figure behind the McGuinty government's refusal to give official party status to the NDP (who fell one seat short of the required number in the general election; they subsequently regained party status through a by-election win).

Unlike many other Liberal MPPs, Duncan does not need to worry about electoral competition from the Progressive Conservative Party (which has a very limited base of support in Windsor). The NDP remains his primary opposition, and could retake the seat in the event of a province-wide resurgence in support.

In late 2004, Duncan was responsible for the creation of a new medical school affiliated with the University of Windsor.