Margaret Mary O'Shaughnessy Heckler (June 21, 1931 - ) was born Margaret Mary O’Shaughnessy in Flushing, Queen’s County, New York. A lawyer by training, she has also served in Congress and as Secretary of Health and Human Services.

Her undergraduate studies began at the University of Leiden in Holland in 1952. After graduating from Albertus Magnus College (B.A.1953) and from Boston College Law School (LL.B. 1956), she was admitted to the bar in Massachusetts. She had also been editor of the Annual Survey of Massachusetts Law.

From 1962 to 1966, Heckler served as an elected Governor’s councilor for the Commonwealth of Massachusetts. She was a delegate to the Republican National Convention in 1964 and 1968 and elected as a Republican to the Ninetieth through the Ninety-Seventh Congresses (January 3, 1967 - January 3, 1983). After losing election to the Ninety-Eighth Congress, Heckler was requested by President Reagan and confirmed by the Senate as Secretary of Health and Human Services from 1983 to 1985. After that, she was appointed United States ambassador to Ireland from December 1985 to August 1989.

Margaret Heckler is currently a resident of Wellesley, Massachusetts.