Loughor (Welsh: Casllwchwr) is a town in the City of Swansea, traditional county of Glamorgan, south Wales. It lies on the estuary of the River Loughor .

The town was home to a Roman fort, over which the Norman Loughor Castle was built in 1099. It later grew as a port, while in the early twentieth century large tin and steel works were the main industries. It is now mostly a commuter town for Swansea and Llanelli and has merged with the neighbouring town of Gorseinon.