| Province: | QC |
| Type: | QC |
| Route: | 172 |
| Maint: | Transports Québec |
| Map: | Route 172-QC.png |
| Length Km: | 169.1 |
| Length Round: | 1 |
| Length Ref: | [1] |
| Direction A: | West |
| Direction B: | East |
| Terminus A: | in Saint-Nazaire |
| Terminus B: | in Tadoussac |
| Previous Type: | QC |
| Previous Route: | 171 |
| Next Type: | QC |
| Next Route: | 173 |
| Junction: | in Saguenay |
Route 172 is an east–west highway on the north shore of the St. Lawrence River in Quebec, Canada, and it parallels the Saguenay River on the north side of it. The western terminus of Route 172 is in Saint-Nazaire at the junction of Route 169, and the eastern terminus is in Tadoussac, at the junction of Route 138.