Deborah Coyne is a Canadian constitutional lawyer and author. She is the sister of journalist Andrew Coyne and actress Susan Coyne , and the daughter of former Governor of the Bank of Canada, James Coyne.

Coyne's daughter Sarah, born in 1991, was fathered by former Canadian Prime Minister Pierre Trudeau. Coyne and Trudeau never married, however, and Coyne later married Canadian journalist Michael Valpy.