The 1970–71 European Cup was the 16th season of the European Cup, UEFA's premier club football tournament. The competition was won by Ajax, who beat Panathinaikos in the final at Wembley Stadium in London, on 2 June 1971. It was the first time the trophy went to Ajax, beginning a three-year period of domination, and the second consecutive championship for the Netherlands. It was also the first time that a Greek team reached the final. There were many reports from the Greek and international press of the time about bribery by Panathinaikos to players of other teams (Everton, Red Star), as well as the active involvement of the Colonels Junta, in order to be able to reach Wembley. However these claims are just speculations and UEFA has denied any accusations.

UEFA had introduced for the first time penalty shoot-out as a way of deciding drawn ties – doing away with the unsatisfactory tossing of a coin. They had also decided that the away goals rule should apply to all rounds, and not just the first two, as had been the case.

This season marked the first time in European Cup history that Real Madrid failed to qualify for the tournament, having appeared in all 15 previous seasons.

Feyenoord, the defending champions, were eliminated by Romanian club UTA Arad in the first round.

Austria Wien won 4–3 on aggregate.

Cagliari won 3–1 on aggregate.

Atlético Madrid won 4–1 on aggregate.

Standard Liège won 7–0 on aggregate.