Cathy Rosier (January 2, 1945, in Fort-de-France – May 17, 2004) was a French model and actress born in Martinique, French West Indies. She died in Marrakech, Morocco, from a ruptured aorta.

Rosier was the daughter of the Martiniquais writer and painter Yva (née de Montaigne) and her husband, politician and mathematics instructor Thélus Léro. She is perhaps best known for her role as the pianist Valerie in Jean-Pierre Melville's Le Samouraï (1967).