The Una da Aldeia River (Portuguese: Rio Una da Aldeia) is a river in the south of the state of São Paulo, Brazil. It is a tributary of the Ribeira de Iguape River.

The Una da Aldeia River originates in the municipality of Juquiá, São Paulo, near the BR-116 highway. In its upper course it is named the Itimirim River It flows in a southeast direction, roughly parallel to the SP-222 highway, entering the municipality of Iguape. It is joined by the Espraiado River from the left, which flows from the Juréia-Itatins Ecological Station. The Una da Aldeia River continues southeast and joins the Ribeira de Iguape River not far from that river's mouth on the Atlantic Ocean.

• List of rivers of São Paulo