| Frades River | |
| Pushpin Map: | Brazil |
| Mouth Location: | Atlantic Ocean |
| Mouth Coordinates: | -16.6894°N -39.1048°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | Brazil |
The Frades River (Portuguese: Rio dos Frades - Friar's River) is a river in the state of Bahia, Brazil.
The river has a drainage basin.Its headwaters rise in the eastern foothills of the Vista Alegre and Pinhão serras at altitudes of 400to.The basin and surrounding watershed cover between the Caraíva River basin to the south, Jucuruçu River basin to the southeast and Buranhém River basin to the north. The Atlantic Ocean is to the east.
The river has a length of . Its source is the Córrego do Frade in the municipality of Guaratinga, Bahia. The córrego runs southeast to meet the Barriguda River, forming the Frades River, which runs east and then southeast to the Atlantic Ocean.The Pau Brasil National Park lies between the Frades and Buranhém rivers.The mouth of the river is protected by the Rio dos Frades Wildlife Refuge, and is an area of restinga salt marsh, with shrubs and thickets. There are mangroves and many bromeliads and orchids.