The eighth Inter-Cities Fairs Cup was played over the 1965–66 season. The competition was won by Barcelona over two legs in an all-Spanish final against Zaragoza. It was the sixth and final time that a Spanish side won the competition, and Barcelona's third title.

First round

First leg

Second leg

Porto won 1–0 on aggregate. Antwerp won 4–3 on aggregate. Wiener won 8–2 on aggregate. Chelsea won 4–1 on aggregate. RC Strasbourg 2–2 Milan on aggregate; play-off needed. Fiorentina won 7–1 on aggregate. Brno won 2–1 on aggregate. Leeds United won 2–1 on aggregate. Valencia 2–2 Hibernian on aggregate; play-off needed.

Play-off

''Milan 1–1 RC Strasbourg in play-off. Milan advanced on a coin toss.'' Valencia won the play-off 3–0.

Second round

First leg

Second leg

Hannover 96 won 6–2 on aggregate. Steagul Roșu Brașov won 3–2 on aggregate. Real Zaragoza won 3–2 on aggregate. Leeds won 2–1 on aggregate. Milan 2–2 GD CUF on aggregate. Milan won 1–0 in play-off. Spartak Brno won 4–2 on aggregate. Valencia won 8–2 on aggregate.

Third round

First leg

Second leg

Steagul Roșu 5–5 Espanyol on aggregate. Chelsea 3–3 Milan on aggregate. ''Milan 1–1 Chelsea in play-off. Chelsea advanced on a coin toss.'' Dunfermline won 2–0 on aggregate. Leeds won 2–1 on aggregate.

Quarter-finals

First leg

Second leg

Leeds won 5–2 on aggregate.

Semi-finals

First leg

Second leg

''Leeds – Zaragoza 2–2 on aggregate, replay is needed. Leeds won toss to play at home'' Zaragoza won 5–3 on aggregate. ''Chelsea – Barcelona 2–2 on aggregate, replay is needed. Barcelona won toss to play at home'' Barcelona won 7–2 on aggregate.

Final