José Roberto Diniz Aranha (born 2 February 1951 in São Paulo) is a former international freestyle swimmer from Brazil, who competed at two consecutive Summer Olympics for his native country, starting in 1968.

[3][4] At the 1968 Summer Olympics, in Mexico City, he swam the 100-metre freestyle and the 4×100-metre medley (along with José Fiolo, João Costa Lima Neto and César Filardi), not reaching the finals.

[5][6][7][8] At the 1972 Summer Olympics, in Munich, he finished 4th in the 4×100-metre freestyle (6 seconds and a half below the South American record), along Ruy de Oliveira, Paulo Zanetti and Paulo Becskehazy, and 5th in the 4×100-metre medley (improving in 5 seconds the South American record), along with Rômulo Arantes, José Fiolo and Sérgio Waismann.

[1][2][9] At the 1973 Summer Universiade, in Moscow, Aranha won a bronze medal in the 4×200-metre freestyle, along with José Namorado, James Huxley Adams and Alfredo Machado.

[10][11] Participated at the inaugural World Aquatics Championships in 1973 Belgrade, where he finished 5th in the 4×100-metre freestyle, along with Ruy de Oliveira, José Namorado and James Huxley Adams.