The 2012 AFC Champions League was the 31st edition of the top-level Asian club football tournament organized by the Asian Football Confederation (AFC), and the 10th under the current AFC Champions League title.

Ulsan Hyundai from South Korea won their first title, losing to Al-Ahli from Saudi Arabia with a 4-1 win in the final,.

The AFC approved criteria for participation in the 2011 and 2012 seasons. The final decision date was set after the Executive Committee meeting in November 2010.

On 30 November 2009, the AFC announced 12 more MA's that were keen to join the ACL, in addition to ten participating national associations. Singapore later withdrew. The full list of candidate associations were as follows:

Note: India, Singapore, Thailand and Vietnam have clubs taking part in play-offs to qualify for the group stages of ACL in 2010.

It was originally announced that the allocation for entry to the 2012 ACL would stay the same as the previous three seasons with the exception of Vietnam, who were disqualified, and their previous playoff slot was awarded to Qatar. However, following the AFC Executive Committee meeting in November 2011, it was decided that the number of slots for each association to be changed based on evaluation of the AFC Champions League criteria that took place in 2011.

A total of eleven member associations (see below) which participated in the 2011 AFC Champions League was evaluated for participating in the 2012 AFC Champions League. India, which played in the 2011 ACL play-off, was not evaluated and dropped to the AFC Cup. The other member associations which applied but did not meet the criteria for 2011 ACL was not evaluated at all for 2012.

A total of 37 teams participated in the 2012 AFC Champions League.