| Saint-Sébastien | |
| Settlement Type: | Municipality |
| Pushpin Map: | Canada Southern Quebec |
| Pushpin Map Caption: | Location in southern Quebec |
| Coordinates: | 45.7833°N -128°W |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Type2: | Region |
| Subdivision Name2: | Estrie |
| Subdivision Type3: | RCM |
| Subdivision Name3: | Le Granit |
| Established Title1: | Constituted |
| Established Date1: | March 15, 1975 |
| Leader Title: | Mayor |
| Leader Name: | France Bisson |
| Leader Title1: | Federal riding |
| Leader Name1: | Mégantic—L'Érable |
| Leader Title2: | Prov. riding |
| Leader Name2: | Mégantic |
| Area Total Km2: | 91.10 |
| Area Land Km2: | 91.95 |
| Area Note: | There is an apparent contradiction between two authoritative sources |
| Population Total: | 674 |
| Population As Of: | 2021 |
| Population Density Km2: | 7.3 |
| Population Blank1 Title: | Pop 2016-2021 |
| Population Blank1: | 2.6% |
| Population Blank2 Title: | Dwellings |
| Population Blank2: | 329 |
| Timezone: | EST |
| Utc Offset: | −5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | −4 |
| Postal Code Type: | Postal code(s) |
| Postal Code: | G0Y 1M0 |
| Area Code: | 819 |
| Blank Name: | Highways |
Saint-Sébastien (pronounced as /fr/) is a municipality in Le Granit Regional County Municipality in the Estrie region of Quebec, Canada. It is named after Saint Sebastian, who died c. 288.
In the 2021 Census of Population conducted by Statistics Canada, Saint-Sébastien had a population of living in of its total private dwellings, a change of from its 2016 population of . With a land area of 91.95km2, it had a population density of in 2021.[1]