| East Branch Oyster River | |
| Mouth Location: | Oyster River |
| Mouth Coordinates: | 44.1137°N -69.1932°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Progression: | Oyster River – Saint George River – Muscongus Bay |
The East Branch Oyster River is a tributary of the Oyster River in Knox County, Maine. From its source (44.1509°N -69.1414°W) in Rockland, the stream runs [1] southwest to its confluence with the main stem of the Oyster River, on the border between Warren and Thomaston.