AFC Champions League

The Asian Football Confederation (AFC) first discussed launching a tournament for the champions of AFC nations in a meeting held on 21 April 1963, with its Secretary Lee Wai Tong announcing the AFC's intention to hold a competition similar to the European Cup. The competition started in 1967 as the Asian Champion Club Tournament and had a variety of different formats in its first few years, with the inaugural tournament staged as a straight knock-out format, and the following three editions consisting of a group stage.

While Israeli clubs dominated the first four editions of the competition, this was partly due to the refusal of Arab clubs to play them:

• In 1970, Lebanese club Homenetmen refused to play Hapoel Tel Aviv in the semi-final, which was scratched with Hapoel advancing to the final.
• In 1971, Aliyat Al-Shorta of Iraq refused to play Maccabi Tel Aviv on three occasions: in the preliminary round (which was redrawn), in the group stage, and then in the final, which was scratched with Maccabi being awarded the championship. During the award ceremony for Maccabi, Aliyat Al-Shorta players waved the Palestinian flag around the field, with a match being arranged by the AFC and the Thai FA between Maccabi and a Combined Bangkok team in lieu of the final. The Iraqi media considered Aliyat Al-Shorta as the tournament's winners, with the team holding an open top bus parade in Baghdad.

After the 1972 edition had to be cancelled by the AFC for various reasons, including two Arab clubs being excluded for refusing to commit to playing against Israeli club Maccabi Netanya, the AFC suspended the competition for 14 years, while Israel would be expelled from the AFC in 1974.

Asia's premier club tournament made its return in 1985 as the Asian Club Championship.

In 1990, the Asian Football Confederation introduced the Asian Cup Winners' Cup, a tournament for the cup winners of each AFC nation, while the 1995 season saw the introduction of the Asian Super Cup, with the winners of the Asian Club Championship and Asian Cup Winners' Cup playing against each other.

The 2002–03 season saw the Asian Club Championship, Asian Cup Winners' Cup and Asian Super Cup combine to become the AFC Champions League. League champions and cup winners would qualify for the qualifying playoffs with the best eight clubs from East Asia and the eight best clubs from West Asia progressing to the group stage. The first winners under the AFC Champions League name were Al-Ain, defeating BEC Tero Sasana 2–1 on aggregate. In 2004, 29 clubs from fourteen countries participated and the tournament schedule was changed to March–November.

In the group stage, the 28 clubs were divided into seven groups of four on a regional basis, separating East Asian and West Asian clubs to reduce travel costs, and the groups were played on a home and away basis. The seven group winners along with the defending champions qualified to the quarter-finals. The quarter-finals, semi-finals, and finals were played as a two-legged format, with away goals, extra time, and penalties used as tie-breakers.

The 2005 season saw Syrian clubs join the competition, thus increasing the number of participating countries to 15, and two years later, following their transfer into the AFC in 2006, Australian clubs were also included in the tournament. However, many blamed the low prize money at that time and expensive travel cost as some of the reasons. The Champions League was expanded to 32 clubs in 2009 with direct entry to the top ten Asian leagues. Each country received up to 4 slots, though no more than one-third of the number of teams in that country's top division, rounded downwards, depending on the strength of their league, professional league structure, marketability, financial status, as well as other criteria set by the AFC Pro-League Committee. The assessment criteria and ranking for participating associations are revised by AFC every two years.

The old format saw the eight group winners and eight runners-up qualify to the round of 16, in which group winners played host to the runners-up in two-legged series, matched regionally, with away goals, extra time, and penalties used as tie-breakers. The regional restriction continues all the way until the final, although clubs from the same country couldn't face each other in the quarterfinals unless that country has three or more representatives in the quarterfinals. Since 2013, the final has also been held as a two-legged series, on a home and away basis.

In 2021, the group stage was expanded from 32 to 40 teams, with both the West and East Regions having five groups of four teams. The slot allocation for the top six member associations in each region remained unchanged. The 10 group winners and top 3 runners-up per region are now seeded based on a combination table for the round of 16, with the games still matched regionally until the final.

On 25 February 2022, it was announced that the AFC Champions League would go back to an inter-year (autumn to spring) schedule starting with the 2023–24 season. In addition, the existing "3+1" rule for foreign players during matches (3 foreign players and 1 Asian foreigner) was expanded to "5+1" (5 foreign players and 1 Asian foreigner).

By 2021, the various problems with the Iranian sides were attracting media attention; international Arabic and English-language media reported the violation of women's rights in the stadiums of Iranian sides.

On top of that, Iranian women were banned from football stadiums for about 40 years, by the Iranian government. In 2019, Iranian women were first allowed to watch football at stadiums, but not during ACL games. Before that, FIFA had pressured Iran to let women into the stadiums; Iran relented, but capped the number of women to watch the 2018 final. In 2021, the AFC investigated the matter, in the hope of allowing unrestricted attendance whenever Iranian clubs are involved.

On 23 December 2022, the AFC announced that their club football structure would undergo an overhaul, with the top club competition shrinking from 40 teams in the main stage to 24 teams, divided into East and West regions (12 teams each), with each team in the East and West regions playing eight other teams from their region (four teams at home and four teams away). The top eight teams from each region would advance to the knockout stage, where only the round of 16 would be played over two legs, with all matches from the quarter-finals onward being played in a single-leg format at a centralised venue. On 14 August 2023, it was confirmed that the new format would come into effect from the 2024–25 season, with the name of the competition changing to AFC Champions League Elite. The AFC has also confirmed that AFC Champions League records and statistics would be carried forward to the ACL Elite. In December 2023, Saudi Arabia were awarded hosting duties for the final stage for the first two seasons.