| Saint-Thomas-Didyme | |
| Flag Size: | 120x100px |
| Mapsize: | 200px |
| Pushpin Map: | Canada Lac-Saint-Jean Quebec |
| Pushpin Label Position: | top |
| Pushpin Map Caption: | Location in Saguenay–Lac-Saint-Jean Quebec. |
| Coordinates: | 48.9°N -112°W |
| Subdivision Type: | Country |
| Established Title: | Settled |
| Established Date: | 1910s |
| Established Title1: | Constituted |
| Established Date1: | May 11, 1923 |
| Government Footnotes: | [1] |
| Leader Title: | Mayor |
| Leader Name: | Denis Tremblay |
| Area Footnotes: | [2] |
| Area Total Km2: | 357.20 |
| Area Land Km2: | 333.25 |
| Population Total: | 703 |
| Population As Of: | 2021 |
| Population Density Km2: | 2.1 |
| Population Blank1 Title: | Pop (2016–21) |
| Population Blank1: | 4% |
| Population Blank2 Title: | Dwellings |
| Population Blank2: | 518 |
| Utc Offset: | −5 |
| Utc Offset Dst: | −4 |
Saint-Thomas-Didyme is a municipality in Maria-Chapdelaine Regional County Municipality in the Saguenay–Lac-Saint-Jean region of Quebec, Canada. It had a population of 703 in the Canada 2021 Census.
Population trend:[3]
Private dwellings occupied by usual residents: 364 (total dwellings: 518)
Mother tongue:[4]