| Saint-Justin | |
| Settlement Type: | Municipality |
| Motto: | Cruce et Aratro ("By the Cross and the Plough") |
| Pushpin Map: | Canada Central Quebec |
| Pushpin Label Position: | left |
| Pushpin Map Caption: | Location in central Quebec |
| Coordinates: | 46.25°N -78°W |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Type2: | Region |
| Subdivision Name2: | Mauricie |
| Subdivision Type3: | RCM |
| Subdivision Name3: | Maskinongé |
| Established Title1: | Constituted |
| Established Date1: | July 1, 1855 |
| Leader Title: | Mayor |
| Leader Name: | Christian Girouard |
| Leader Title1: | Federal riding |
| Leader Name1: | Berthier—Maskinongé |
| Leader Title2: | Prov. riding |
| Leader Name2: | Maskinongé |
| Area Total Km2: | 79.60 |
| Area Land Km2: | 78.96 |
| Population Total: | 961 |
| Population As Of: | 2021 |
| Population Density Km2: | 12.2 |
| Population Blank1 Title: | Pop 2016-2021 |
| Population Blank1: | 1.2% |
| Population Blank2 Title: | Dwellings |
| Population Blank2: | 511 |
| Timezone: | EST |
| Utc Offset: | −5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | −4 |
| Postal Code Type: | Postal code(s) |
| Postal Code: | J0K 2V0 |
| Area Code: | 819 |
| Blank Name: | Highways |
| Blank Info: | No major routes |
Saint-Justin is a municipality in the Mauricie region of the province of Quebec in Canada.
On December 6, 2014, Saint-Justin changed from parish municipality to a (regular) municipality.[1]