The 2024–25 UEFA Champions League season first used a 36-team league phase.
The reform replaced the previous group-stage structure, which had contained 32 clubs divided into eight groups of four. Instead, all 36 teams were placed in one league table. Each club played eight matches against eight different opponents: four at home and four away.
The new format also changed qualification for the knockout rounds. The top eight teams in the league table advanced directly to the round of 16. Clubs finishing ninth through 24th entered knockout play-offs, while teams placed 25th or lower were eliminated from the competition.
The 2024–25 campaign was the first season of the new system, not the 2025–26 season. It was also the 70th season of Europe's premier club competition and the 33rd since the tournament adopted the Champions League name. The change was designed to create more high-profile fixtures and give four additional clubs access to the main phase.