Margaret Mary O'Shaughnessy Heckler (born 1931) was an attorney, congressional representative, Secretary of Health and Human Services, and Ambassador to the Republic of Ireland.

Margaret Heckler was born in Flushing, New York, in 1931, the daughter of John and Alice O'Shaughnessy. She graduated from Albertus Magnus College, where she had been a political science major and active in student politics, in 1953. She met her husband, John, a stockbroker, while in college, and, although they were divorced in 1984, he was a strong supporter of her political ambitions during most of their 30-year marriage. The Hecklers had three children: Belinda, Alison, and John.

In 1956 Heckler was the only woman in her graduating class at Boston College Law School, where she had been elected editor of the Law Review. She entered Massachusetts politics in 1962 as the first woman elected to the Governor's Council. In 1966 she was elected as a Republican to the U...