Azellus Denis, PC QC (March 26, 1907 – September 4, 1991) was a Canadian politician who served in the Parliament of Canada as a Member of Parliament and Senator for the longest period of time, 55 years, 10 months and 20 days. Born in Saint-Norbert, Quebec, the son of Arsène Denis and Georgiana Laporte, he was educated in Saint-Norbert, Joliette and at the Université de Montréal. Denis practised law in Montreal. In 1945, he married Émérencienne Fleury-Bissonnette. He was a reservist in the 2nd Battalion (Reserve) Châteauguay Regiment.