Odilon Desmarais, KC (February 27, 1854 – May 18, 1904) was a lawyer, judge and political figure in Quebec. He represented Saint-Hyacinthe in the Legislative Assembly of Quebec from 1890 to 1892 and St. James in the Canadian House of Commons from 1896 to 1901 as a Liberal.He was born in Joliette, Canada East, the son of Jean-Baptiste Desmarais and Émérentienne Beauchamps, and was educated at the Collège de Joliette and McGill University.