Marion Boyd (born March 26, 1946 in Toronto, Ontario) is a former Canadian politician, who represented the riding of London Centre in the Legislative Assembly of Ontario from 1990 to 1999 as a member of the Ontario New Democratic Party.

In 1968, Boyd graduated from Glendon College with an Honours Bachelor of Arts in English and History. From 1968 to 1973, she worked as an assistant to the president of York University. In 1975-76, she helped the York University Faculty Members win their first union contract. She subsequently worked as an executive director of the London Battered Women's Advocacy Clinic, and served two terms as president of the London Status of Women Action Group.

Boyd's first campaigns for public office were unsuccessful. She was the NDP candidate in London North in the provincial election of 1985, but finished a distant third against incumbent Liberal Robert Van Horne and a Progressive Conservative. She ran in London Centre in the 1987 election, and lost to sitting Premier David Peterson by almost 9,000 votes. She campaigned as a federal New Democrat in the 1988 general election, finished third behind Liberal Joe Fontana and Progressive Conservative Jim Jepson in London East .

The Ontario New Democratic Party won an unexpected victory in the 1990 provincial election, and Boyd scored a shocking landslide victory over David Peterson in London Centre, defeating the Premier by more than 8,000 votes. She was appointed Minister of Education on October 1, 1990. She also received responsibility for Women's Issues on September 11, 1991, and launched a high-profile campaign against domestic abuse in the same year. She was transferred to the Ministry of Community and Social Services on October 15, 1991.

Boyd was promoted to Attorney General of Ontario on February 3, 1993, the first woman to hold that position. In this capacity, she was responsible for the Rae government's controversial bill recognizing benefits to same-sex couples, which ultimately failed on a free vote when twelve NDP members voted with the opposition parties against the bill. The bill's failure was a personal disappointment for Boyd, who had invested considerable effort into promoting its passage.

Boyd also approved a highly controversial plea-bargain deal that allowed serial killer Karla Homolka to receive a relatively light prison sentence in return for testimony which led to the conviction of Homolka's then-husband, Paul Bernardo. This deal was criticized in much of the Canadian media, and many questioned Boyd's judgement in the matter. (In fairness, it should be noted that the extent of Homolka's personal involvement in Bernardo's crimes was not widely known at the time.)

Boyd remained as Attorney General until the Rae government was defeated in the 1995 election. She was one of seventeen NDP MPPs to successfully retain a legislative seat in that election, defeating PC candidate Patrick McGuinness by fewer than 2,000 votes. Boyd remained a high-profile MPP, serving as the NDP's Health Critic from 1997 to 1999.

The London Centre riding was eliminated by redistribution in 1996. Boyd ran against fellow incumbent Dianne Cunningham of the Progressive Conservative Party in London North Centre, and lost by just over 1,700 votes.

Boyd currently works as an environmental business consultant and mediator. In December, 2004, she released a controversial study which recommended that the Ontario government permit the adoption of sharia tribunals for Muslims who wished to have family arbitration disputes settled in that manner.