The 2012–13 LEN Champions League was the 50th edition of LEN's premier competition for men's water polo clubs. It ran from 14 September 2012 to 1 June 2013, and it was contested by thirty teams from eighteen countries. There was no defending champion as Pro Recco renounced to the competition for disagreements with the FIN on the number of allowed foreign players in the Italian clubs' squads. Runner-up Primorje Rijeka, former champions Mladost Zagreb and Vasas Budapest, Italy's CN Posillipo and any team from Montenegro also declined to take part in the competition. The Final Four (semifinals, final, and third place game) took place on May 31 and June 1 in Belgrade.