Ruy Tadeu Aquino de Oliveira (born 1 February 1953) is a former international freestyle swimmer from Brazil, who competed at one Summer Olympics for his native country.

[1][2][3] He was at the 1971 Pan American Games, in Cali, where he won two bronze medals, in the 4×100-metre freestyle and in the 4×200-metre freestyle, both breaking the South American record.

[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).

[2][9] Participated at the inaugural World Aquatics Championships in 1973 Belgrade, where he finished 5th in the 4×100-metre freestyle, along with José Aranha, José Namorado and James Huxley Adams; and 8th in the 100-metre freestyle.

In the 4×100-metre medley, he finished 9th, with a time of 4:01.99, along with Rômulo Arantes, Heliani dos Santos and Sérgio Pinto Ribeiro.