Louis R. Desmarais (16 February 1923 – 25 March 2017) was a Liberal party member of the House of Commons of Canada. He was a Chartered Accountant by career. In 1968 he became president of Les Entreprises de Transport Provincial limitée and was Président of Canada Steampship line whose head manager in Quebec city was André Poliquin. His brother Jean Noël Desmarais was a physician and senator, and his brother Paul Desmarais was a billionaire businessman.