| Gain Creek | |
| Pushpin Map: | CAN BC Capital#Canada British Columbia |
| Pushpin Map Caption: | Location of the mouth of Gain Creek |
| Pushpin Map Alt: | Maps with a red dot at the mouth of Gain Creek |
| Subdivision Type1: | Country |
| Subdivision Name1: | Canada |
| Subdivision Type2: | Province |
| Subdivision Name2: | British Columbia |
| Subdivision Type3: | District |
| Subdivision Name3: | Capital Regional District |
| Source1: | unnamed confluence |
| Source1 Location: | San Juan Ridge |
| Source1 Coordinates: | 48.545°N -124.1706°W |
| Source1 Elevation: | 637m (2,090feet)[1] |
| Mouth: | Loss Creek |
| Mouth Coordinates: | 48.4964°N -124.2047°W |
Gain Creek is a river in the Capital Regional District of British Columbia, Canada. Located on southern Vancouver Island, it flows from its source to its mouth as a right tributary of Loss Creek.
Gain Creek begins at an unnamed confluence on the south slope of the San Juan Ridge at an elevation of . It flows southwest, and reaches its mouth as a right tributary of Loss Creek at an elevation of, south east of the settlement of Port Renfrew. Loss Creek flows to the Strait of Juan de Fuca on the Pacific Ocean.