| Olaüs Thérien | |
| Constituency Mp: | Montcalm |
| Parliament: | Canadian |
| Predecessor: | Firmin Dugas |
| Successor: | Joseph Louis Euclide Dugas |
| Term Start: | 1887 |
| Term End: | 1891 |
| Birth Date: | 3 September 1860 |
| Birth Place: | Ste-Anne-des-Plaines, Canada East |
| Party: | Conservative |
Olaüs Thérien (September 3, 1860 - December 31, 1929) was a Canadian lawyer, editor and political figure in Quebec, Canada. He represented Montcalm in the House of Commons of Canada from 1887 to 1891 as a Conservative member.
He was born in Ste-Anne-des-Plaines, Canada East, the son of Pierre Thérien and Claire Derouin, and was educated at the Petit Séminaire de Saint-Thérèse and Université Laval. He was called to the Quebec bar in 1885. Thérien was defeated when he ran for reelection in 1891.