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.

[1] He was first elected as a Liberal Member of Parliament in the riding of St. Denis in 1935.

His brother Arthur had represented the St. Denis riding in the House of Commons until his death in 1934.

In the midst of the scandal, he was appointed to the Senate at the recommendation of Prime Minister Lester B. Pearson and served until his death in 1991.

After his death in 1991, he was entombed at the Notre Dame des Neiges Cemetery in Montreal.