Lyn McLeod OOnt (born c. 1942) is a former politician in Ontario, Canada. She served in the Legislative Assembly of Ontario from 1987 to 2003. McLeod was a cabinet minister in the Liberal government of David Peterson from 1987 to 1990, and served as leader of the Ontario Liberal Party from 1992 to 1996.

McLeod graduated from the University of Manitoba and received a Master of Arts degree in Psychology from Lakehead University, in the Northern Ontario city of Thunder Bay. She was trustee on the Lakehead Board of Education for seventeen years and its chair for seven. McLeod was also appointed to the Board of Governors of Lakehead University in 1986.

She was married to the late Neil McLeod, a prominent Thunder Bay family physician.

She was elected for the riding of Fort William in the provincial election of 1987, defeating incumbent Progressive Conservative Michael Hennessy by 1,463 votes. The Liberals won a landslide majority in this election and made several historical breakthroughs in Northern Ontario. McLeod was appointed Minister of Colleges and Universities on September 29, 1987. Following a cabinet shuffle on August 2, 1989, she was named Minister of Energy and Minister of Natural Resources.

The Liberals were upset by the New Democratic Party in the provincial election of 1990, although McLeod was able to retain her riding against a strong challenge from NDP candidate Dan Hutsul, winning by 1,345 votes. Unlike most other Liberal candidates in this election, McLeod was supported by prominent members from the Ontario Secondary School Teachers' Federation in her region.

Peterson personally lost his seat in the 1990 campaign, and the Liberal party went through a series of interim leaders before holding a leadership convention in early 1992. McLeod was one of six candidates for the position, and was widely regarded as the main challenger to frontrunner Murray Elston. She finished a strong second on the first ballot, and overtook Elston on the third with support from Steve Mahoney's delegates. McLeod's people had made a deal with second-tier leadership contender Charles Beer. The Elston camp had an unexpectedly large lead on the first ballot, as McLeod lent Beer some of her delegates to give him a respectable showing, and Elston's margin dropped significantly when the eliminated Beer threw his full support behind McLeod. McLeod finally defeated Elston by nine votes on the fifth ballot, becoming the first woman to lead a major party in Ontario.

With Bob Rae's NDP government being widely blamed for mishandling the major recession, McLeod's Liberals held a steady lead in the polls for most of the period from 1992 to 1995, and were generally expected to win the 1995 campaign. The party, however, damaged its credibility through a series of high-profile policy reversals in the period leading up to the election.

The most notable of these occurred when McLeod withdrew Liberal support for the proposed Equality Rights Statute Amendment Act (Bill 167), which would have granted same-sex couples most of the same rights as opposite-sex common law couples, introduced by the NDP government of Bob Rae in 1994. The legislation was defeated after the majority of Liberal MPPs and twelve NDP MPPs joined with the entire Progressive Conservative caucus in voting against it. Many regarded McLeod's decision as cynical and opportunistic, and some believe that it was intended to boost Liberal fortunes in rural areas following a by-election loss in the rural, socially conservative riding of Victoria—Haliburton. The result, however, was that the party earned a reputation for "flip-flopping" and inconsistency, while offending its socially progressive supporters.