San Xoán de Río is a municipality in the province of Ourense, in the autonomous community of Galicia, Spain.

It belongs to the comarca of Terra de Trives.

It is named after Saint John (Galician: San Xoán), the local patron.

The village of Domecelle is located within the municipality.

This article about a location in the autonomous community of Galicia, Spain is a stub.