The 1971 U.S. Men's Clay Court Championships was a men's tennis tournament that was part of the 1971 Grand Prix circuit. The event was held in Indianapolis, USA and played on outdoor clay courts. It was the 3rd edition of the tournament in the Open Era and was held in from 16 August through 22 August 1971. Željko Franulović won the singles title.
Željko Franulović defeated Cliff Richey 6–3, 6–4, 0–6, 6–3
Željko Franulović / Jan Kodeš defeated Clark Graebner / Erik Van Dillen 7–6, 5–7, 6–3