Margaret Helen Harrington (born October 4, 1945 in Warwick, England) is a politician in Ontario, Canada. She was a New Democratic Party member of the Legislative Assembly of Ontario from 1990 to 1995.

Harrington was educated at Queen's University in Kingston, Ontario, receiving a Bachelor of Science degree in Biochemistry. She worked as a secondary school teacher in Niagara Falls after her graduation, and served on the Niagara Falls city council. In 1988, she was named Niagara Falls Woman of the Year. Her husband, Dick Harrington , ran for the federal and provincial New Democratic Party on three occasions.

Margaret Harrington first ran for the Ontario legislature in the 1987 provincial election, and finished second against Liberal Vince Kerrio in the riding of Niagara Falls . Three years later, in the 1990 provincial election, Harrington defeated Liberal candidate Wayne Campbell by almost 6,000 votes in the same riding, amid an unexpected NDP majority victory across the province. Harrington served as parliamentary assistant to the Minister of Housing from 1990 to 1993, when she was appointed as a Deputy Speaker.

The NDP were defeated in the 1995 provincial election, and Harrington finished third against Progressive Conservative Bart Maves in her bid for re-election. She has not sought a return to provincial politics since this time.

Harrington is now a real estate salesperson in Niagara Falls.