| Province: | QC |
| Type: | QC |
| Route: | 338 |
| Maint: | Transports Québec |
| Map: | Route 338-QC.png |
| Length Km: | 40.9 |
| Length Round: | 1 |
| Length Ref: | [1] |
| Direction A: | West |
| Direction B: | East |
| Terminus A: | at the Ontario border (formerly) |
| Terminus B: | in Vaudreuil-Dorion |
| Previous Type: | QC |
| Previous Route: | 337 |
| Next Type: | QC |
| Next Route: | 339 |
| Counties: | Vaudreuil-Soulanges |
| Cities: | Coteau-du-Lac, Vaudreuil-Dorion |
| Junction: | in Rivière-Beaudette in Coteau-du-Lac in Les Cèdres |
Route 338 is a provincial highway located in the Montérégie region of Quebec west of Montreal. The highway runs from the Ontario Border near Rivière-Beaudette as a continuation of Stormont, Dundas and Glengarry County Road 2 and ends at Vaudreuil-Dorion at the junction of Autoroute 20 which the 338 acts as an alternate and service route parallel to A-20 although through several villages along the Saint Lawrence River. Before the 1970s, this road was named "Route 2", as part of an interprovincial Route 2 that stretched from Windsor, Ontario to Halifax, Nova Scotia.