เอเอฟซีแชมเปียนส์ลีก 2021
ทีม

ด้านล่างนี้คือ 52 ทีมที่มาจาก 23 สมาคมที่เข้าร่วมการแข่งขัน.
ในตารางด้านล่างนี้, จำนวนของการลงสนามและการลงสนามครั้งล่าสุดนับเฉพาะตั้งแต่ฤดูกาล 2002–03 (รวมไปถึงรอบคัดเลือก), เมื่อการแข่งขันได้ถูกเปลี่ยนชื่อมาเป็น เอเอฟซีแชมเปียนส์ลีก.
หมายเหตุ: เฉพาะทีมที่มั่นใจในพื้นที่นั้นที่จะแสดงให้เห็น.
^ แชมป์เก่า (TH): อุลซันฮุนได คือ แชมป์เก่า.
^ Australia (AUS): Wellington Phoenix, the 2019–20 A-League regular season third place, are a team from New Zealand and thus ineligible to represent Australia in AFC club competitions. As a result, Brisbane Roar, the regular season fourth place, qualify for the 2021 AFC Champions League as Australia 3.
^ Iraq (IRQ): Due to the COVID-19 pandemic in Iraq, the 2019–20 Iraqi Premier League and the 2019–20 Iraq FA Cup were cancelled and declared null and void by the Iraq Football Association. Originally a play-off was to be held to determine the teams from Iraq playing in the 2021 AFC Champions League. However, it was later decided that the results of the previous domestic season (2018–19 Iraqi Premier League and 2018–19 Iraq FA Cup) would be used.
^ South Korea (KOR): Sangju Sangmu, the 2020 K League 1 fourth place, are a military team and have confirmed that the team would move its franchise city in the 2021 season and would be relegated to K League 2 regardless of their final position in the 2020 season. As a result, Daegu FC, the league fifth place, qualify for the 2021 AFC Champions League as South Korea 4.
^ Philippines (PHI): Due to the COVID-19 pandemic in the Philippines, the 2020 Copa Paulino Alcantara was cancelled and not organized by the Philippine Football Federation. As a result, the 2020 Philippines Football League runners-up qualify for the 2021 AFC Champions League as Philippines 2.
^ Singapore (SIN): Albirex Niigata (S), the 2020 Singapore Premier League champions, is a team from Japan and thus ineligible to represent Singapore in AFC club competitions. As a result, Tampines Rovers, the league runners-up, qualify for the 2021 AFC Champions League as Singapore 1.
^ Thailand (THA): Due to the COVID-19 pandemic in Thailand, the Football Association of Thailand extended both the 2020 Thai League 1 and 2020 Thai FA Cup to be completed in 2021. The teams from Thailand playing in the 2021 AFC Champions League are determined by the league positions of the 2020–21 Thai League 1 after the first half of the season.
^ Turkmenistan (TKM): Altyn Asyr, the 2020 Ýokary Liga champions, were not granted an AFC Champions League license. As a result, Köpetdag, the league fourth place and the only team granted an AFC Champions League license, qualify for the 2021 AFC Champions League as Turkmenistan 1.
^ United Arab Emirates (UAE): Due to the COVID-19 pandemic in the United Arab Emirates, the 2019–20 UAE Pro League and the 2019–20 UAE President's Cup were cancelled and declared null and void by the United Arab Emirates Football Association. The teams from the United Arab Emirates playing in the 2021 AFC Champions League are determined by the results of the previous domestic season (2018–19 UAE Pro League and 2018–19 UAE President's Cup).
^  Uzbekistan (UZB): Nasaf, the 2020 Uzbekistan Super League runners-up, were not granted an AFC Champions League license. As a result, AGMK, the league third place and the next team granted an AFC Champions League license, qualify for the 2021 AFC Champions League as Uzbekistan 2.