| Gaston Demers | |
| Office1: | Ontario MPP |
| Term Start1: | 1963 |
| Term End1: | 1971 |
| Predecessor1: | Rhéal Bélisle |
| Successor1: | Floyd Laughren |
| Constituency1: | Nickel Belt |
| Party: | Progressive Conservative |
| Birth Date: | 23 November 1935 |
| Death Place: | Sudbury, Ontario, Canada |
| Occupation: | Stock broker, real estate investor |
| Spouse: | Doreen nee McDonald Demers |
| Children: | Lisa Renee Demers and Lianne Carmel Demers |
Gaston Joseph Clément Demers (November 23, 1935 – February 7, 2004) was a politician in Ontario, Canada. He was a Progressive Conservative member of the Legislative Assembly of Ontario from 1963 to 1971 who represented the northern Ontario riding of Nickel Belt.
Before entering politics, Demers had worked as a journalist for the North Bay Nugget and as a town clerk in Chelmsford. At the time of his election, he was the youngest Member of Provincial Parliament ever elected to the provincial legislature.
After leaving politics, he served on the boards of FedNor and of Sudbury's Laurentian Hospital, and was a key lobbyist behind the creation of Collège Boréal.