Elmer Buchanan (born 1946 in Havelock, Ontario) is a politician in Ontario, Canada. He was a New Democratic Party member of the Legislative Assembly of Ontario from 1990 to 1995, and was a cabinet minister in the government of Bob Rae.

Buchanan has a Bachelor of Arts degree from Queen's University, and a certificate from Teacher's College in Peterborough County. He worked as a high-school teacher in Hastings County, and was vice-principal of North Hastings High School for four years.

Buchanan campaigned for provincial office several times before his election in 1990. He first ran for the Ontario legislature in the 1977 provincial election, but finished a distant third in the riding of Hastings—Peterborough against Progressive Conservative Clarke Rollins . He ran again in the elections of 1981, 1985 and 1987, each time finishing third against Progressive Conservative Jim Pollock . It may be noted that the NDP have not historically been strong in rural eastern Ontario, where the Hastings—Peterborough riding is located.

The NDP won an unexpected majority government under Bob Rae in the provincial election of 1990, and Buchanan defeated Pollock by 896 votes in his fifth attempt for office. He was named Minister of Agriculture and Food on October 1, 1990, and held this position for the entirety of the Rae government. (On March 9, 1994, it was renamed as the Ministry of Agriculture, Food and Rural Affairs.)

Buchanan was one of the most successful ministers in the Rae government, and was widely praised for his handling of the agriculture portfolio. While the Ontario NDP lost much of its rural support between 1990 and 1995, Buchanan remained personally popular within rural Ontario and with the agricultural community. (Interestingly, one of his strongest bases of support was in northern Hastings County, which generally supported candidates of the Progressive Conservative Party and Reform Party at the federal level during this period.) Buchanan stablized funding to many rural centres in 1994, and was a supporter of fuel ethanol throughout his time in government. He also promoted a rural investment pool, and extended unionization rights to farm workers while ensuring that farms with fifty or fewer employees would not be affected.

The NDP were defeated in the provincial election of 1995, and Buchanan's personal popularity was not enough to save him from the party's loss of support in rural areas. He lost to Progressive Conservative Harry Danford by almost 8,000 votes, amid a provincial majority for the Progressive Conservative Party.

Despite some cutbacks during Ontario's recession of the early 1990s, the agriculture ministry had a budget of about $600 million in 1994, kept an agricultural representative in each of the 52 county offices. By 2000, under the government of Mike Harris, the budget had been cut to $300 million and the local representatives had been eliminated.

Buchanan initially considered running for the leadership of the NDP in 1996, but declined. He was instead elected as treasurer of the Ontario NDP, and set tough targets for eliminating the party's post-1995 debt. He also served as a vice-president on the party's executive, and became a board member of the Children's Aid Society .

Buchanan remains active within the Ontario New Democratic Party. In early 2005, he assisted the party's by-election campaign in the rural riding of Dufferin—Peel—Wellington—Grey.