The 2025–26 ASEAN Club Championship knockout stage began on 6 May with the semi-finals and ended on 27 May 2026 with the final.[1] A total of 4 teams competed in the knockout stage to decide the champions of the 2025–26 ASEAN Club Championship.[2]
Each tie in the knockout stage, apart from the final, was played over two legs, with each team playing one leg at home. The team that scored more goals on aggregate over the two legs advanced to the next round. If the aggregate score was level, then 30 minutes of extra time was played (the away goals rule was not applied). If the score was still level at the end of extra time, the winners were decided by a penalty shoot-out. In the final, which was played as a single match, if the score was level at the end of normal time, extra time was played, followed by a penalty shoot-out if the score was still level.[2]