The 2021–22 LEN Euro Cup was the 30th edition of the second-tier European tournament for men's water polo clubs.

[1] The top two ranked sides from each group advance.

[2] The top two ranked sides from each group advance.

[3][4] The four best teams from the Euro Cup qualifications and the four losing sides of the Champions League Qualification Round III have been paired in the quarter-finals.

[5] This article about an international water polo competition is a stub.