| Saint-Janvier-de-Joly | |
| Settlement Type: | Municipality |
| Pushpin Map: | Canada Southern Quebec |
| Pushpin Map Caption: | Location in southern Quebec. |
| Coordinates: | 46.4833°N -111°W |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Type2: | Region |
| Subdivision Name2: | Chaudière-Appalaches |
| Subdivision Type3: | RCM |
| Subdivision Name3: | Lotbinière |
| Established Title1: | Constituted |
| Established Date1: | January 1, 1944 |
| Leader Title: | Mayor |
| Leader Name: | Bernard Fortier |
| Leader Title1: | Federal riding |
| Leader Name1: | Lotbinière— Chutes-de-la-Chaudière |
| Leader Title2: | Prov. riding |
| Leader Name2: | Lotbinière-Frontenac |
| Area Total Km2: | 111.40 |
| Area Land Km2: | 109.88 |
| Population Total: | 1079 |
| Population As Of: | 2021 |
| Population Density Km2: | 9.8 |
| Population Blank1 Title: | Pop 2016-2021 |
| Population Blank1: | 9.7% |
| Population Blank2 Title: | Dwellings |
| Population Blank2: | 500 |
| Timezone: | EST |
| Utc Offset: | −5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | −4 |
| Postal Code Type: | Postal code(s) |
| Postal Code: | G0S 1M0 |
| Area Code: | 418 and 581 |
| Blank Name: | Highways |
Saint-Janvier-de-Joly is a municipality in the Municipalité régionale de comté de Lotbinière in Quebec, Canada. It is part of the Chaudière-Appalaches region and the population is 1,079 as of 2021. It is named after reverend Janvier Lachance, missionary who will serve the parish from 1914 to 1926. "Joly" honours Quebec premier Henri-Gustave Joly de Lotbinière and owner of the seigneurie of Lotbinière, in which part of Saint-Janvier-de-Joly's territory lay.
The post office, opened in 1924, is called Joly, name under which the municipality is most commonly known.