Macha Grenon (born June 7, 1968 in Montreal, Quebec) is a Canadian film and television actress.
Her credits include roles in the television series Urban Angel, Scoop, Le cœur a ses raisons, Emily of New Moon and H2O, as well as the films The Pianist, Stardom, Familia, Windsor Protocol, You Can Thank Me Later, L'Âge des ténèbres, Barney's Version and The Year Dolly Parton Was My Mom. She garnered a Best Actress nomination at the 26th Genie Awards for her performance in Familia.
She has been the partner of film director Denis Villeneuve. Her father, Michel Grenon, was a history professor at the Université du Québec à Montréal, and her grandfather, Hector Grenon, was a historian who wrote several books on the history of Montreal.