Desmarais is a French surname, associated especially but not exclusively with a powerful business and political family in Canada. Notable people with the surname include:
André Desmarais (born 1956), Canadian businessman
Charles Desmarais, president of the San Francisco Art Institute
France Chrétien Desmarais, Canadian lawyer and businesswoman, daughter of Jean Chrétien and wife of André Desmarais
François-Séraphin Régnier-Desmarais (1632–1713), French ecclesiastic, grammarian, diplomat and poet
James Desmarais (born 1979), Canadian professional ice hockey player
Jean Noël Desmarais (1924–1995), Canadian physician, radiologist, and politician and brother of Louis Desmarais
Lorraine Desmarais (born 1956), Canadian jazz pianist and composer
Louis Desmarais (born 1923), member of the Canadian House of Commons from 1979-1984
Ludger Desmarais, professional ice hockey player from 1926–1939
Marcel-Marie Desmarais (1908–1994), Quebec writer, preacher and broadcaster
Odilon Desmarais (1854–1904), Quebec lawyer, judge and politician
Ovide E. Desmarais (1919–1998), American author of books and detective stories
Paul Desmarais (1927–2013), Canadian billionaire and CEO of the Power Corporation of Canada
Paul Desmarais, Jr. (born 1954), Canadian businessman, son of Paul Desmarais, and chairman of Power Corporation of Canada
Pierre DesMarais, Canadian politician and Chairman of Montreal's Executive Committee 1954-1957
