| Constituency Mp: | Glengarry—Prescott—Russell |
| Parliament: | Canadian |
| Predecessor: | Viateur Éthier |
| Successor: | Don Boudria |
| Term Start: | 1972 |
| Term End: | 1984 |
| Birth Date: | 25 March 1926 |
| Birth Place: | Sainte-Justine-de-Newton, Quebec |
| Death Place: | Alexandria, Ontario |
| Nationality: | Canadian |
| Party: | Liberal Party of Canada |
| Relations: | Viateur Éthier, brother |
Denis Éthier (25 March 1926 – 15 March 2017) was a Liberal Party member of the House of Commons of Canada. His career included business such as merchandising.[1]
Éthier represented the Ontario riding of Glengarry—Prescott—Russell which he first won in the 1972 federal election. He replaced his brother Viateur Éthier, who had represented the riding under its previous name Glengarry—Prescott since 1962. He was re-elected there in 1974, 1979 and 1980. He left federal politics in 1984 and did not participate in that year's federal election after serving four consecutive terms from the 29th to the 32nd Canadian Parliaments.