Clarence (Clarie) Gillis, MP (October 3, 1895 – December 17, 1960) was a Canadian social democratic politician and trade unionist from Cape Breton Island, Nova Scotia. He was born on Nova Scotia's mainland, but grew up in Cape Breton. He worked in the island's underground coal mines operated by the British Empire Steel and Coal Company (BESCO). He also served as a member of the infantry in the Canadian Corps in Flanders during the First World War. After the war he returned to the coal mines and became an official with the mine's United Mine Workers of America (UMW) union. In 1938, he helped bring UMW Local 26 into the Co-operative Commonwealth Federation (CCF), becoming the first labour local to affiliate with the party. In 1940, he became the first CCF member elected to the House of Commo