The 1971 ATP Buenos Aires, also known as the South American Open Championships, was a combined men's and women's tennis tournament played on outdoor clay courts and held in Buenos Aires, Argentina.

The men's event was part of the 1971 Pepsi-Cola Grand Prix.

The even was held from 25 November though 1 December 1971.

Željko Franulović and Helga Masthoff won the singles titles.

[1][2] Željko Franulović defeated Ilie Năstase 6–3, 7–6, 6–1 Helga Masthoff defeated Heide Orth 6–4, 7–5 Željko Franulović / Ilie Năstase defeated Patricio Cornejo / Jaime Fillol Sr. Helga Masthoff / Heide Orth defeated Ana María Pinto Bravo / Raquel Giscafré 6–0, 6–2