| Tourney Name: | European Cup |
| Year: | 1970–71 |
| Size: | 300px |
| Dates: | 18 August 1970 – 2 June 1971 |
| Num Teams: | 33 |
| Champion Other: | Ajax |
| Count: | 1 |
| Second Other: | Panathinaikos |
| Matches: | 63 |
| Goals: | 210 |
| Attendance: | 1848876 |
| Top Scorer: | Antonis Antoniadis (Panathinaikos) 10 goals |
| Prevseason: | 1969–70 |
| Nextseason: | 1971–72 |
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.
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.
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Austria Wien won 4–3 on aggregate.
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Cagliari won 3–1 on aggregate.----Atlético Madrid won 4–1 on aggregate.----Standard Liège won 7–0 on aggregate.----Legia Warsaw won 6–1 on aggregate.----Ajax won 4–2 on aggregate.----4–4 on aggregate; Basel won on away goals.----Waterford won 4–1 on aggregate.----Celtic won 14–0 on aggregate.----Carl Zeiss Jena won 5–0 on aggregate.----Sporting CP won 9–0 on aggregate.----Red Star Belgrade won 4–2 on aggregate.----1–1 on aggregate; UTA Arad won on away goals.----Borussia Mönchengladbach won 16–0 on aggregate.----Everton won 9–2 on aggregate.----Panathinaikos won 7–1 on aggregate.----Slovan Bratislava won 4–3 on aggregate.
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Atlético Madrid won 4–2 on aggregate.----Legia Warsaw won 2–1 on aggregate.----Ajax won 5–1 on aggregate.----Celtic won 10–2 on aggregate.----Carl Zeiss Jena won 4–2 on aggregate.----Red Star Belgrade won 6–1 on aggregate.----2–2 on aggregate; Everton won on penalties.----Panathinaikos won 4–2 on aggregate.
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2–2 on aggregate; Atlético Madrid won on away goals.----Ajax won 3–1 on aggregate.----Red Star Belgrade won 6–3 on aggregate.----1–1 on aggregate; Panathinaikos won on away goals.
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Ajax won 3–1 on aggregate.----4–4 on aggregate; Panathinaikos won on away goals.
See main article: 1971 European Cup Final.
The top scorers from the 1970–71 European Cup (excluding preliminary round) are as follows:
