The Tietê River is a Brazilian river in the state of São Paulo.
The source is in Salesópolis in the Serra do Mar, at 1,120 m altitude. Although the source is no more than 22 kilometres away from the coast, the escarpment of the Serra do Mar forces it to run in the opposite direction, to the interior, going through the state of São Paulo from southeast to northwest till it runs into the artificial lake formed by Eng Souza Dias Dam on the Paraná River, in the municipality of Três Lagoas, about 50 kilometres from the city of Pereira Barreto.
The name Tietê was registered for the first time on a map published in 1748 by d’Anville. The name signifies "The truthful river", or "truthful waters" in Tupi.