2020–21 Thai League 2

The 2020–21 Thai League 2 is the 23nd season of the Thai League 2, the second-tier professional league for Thailand's association football clubs, since its establishment in 1997, also known as M-150 Championship due to the sponsorship deal with M-150. A total of 18 teams will compete in the league. The season began on 14 February 2020 and is scheduled to conclude on 31 March 2021.

For this season two teams in the final table (champion and runner up) directly promoted to Thai League 1 next season while teams ranked 3rd - 6th qualified in play off for last spot in top tier next season.

The 1st transfer window is from 19 November 2019 to 10 February 2020 while the 2nd transfer window is from 15 June 2020 to 12 July 2020.

Team changes
The following teams have changed division since the 2019 season.

To Thai League 2

 * Promoted from Thai League 3


 * Khon Kaen United
 * Nakhon Pathom United
 * Phrae United
 * Ranong United
 * Relegated from Thai League 1


 * Chainat Hornbill
 * Chiangmai

From Thai League 2

 * Promoted to Thai League 1


 * BG Pathum United
 * Police Tero
 * Rayong


 * Relegated to Thai League 4


 * Ubon United


 * Withdrew


 * Thai Honda
 * Army United

Renamed Clubs

 * Air Force United was renamed and moved to Uthai Thani
 * JL Chiangmai United renamed Chiangmai United

Personnel
Note: Flags indicate national team as has been defined under FIFA eligibility rules. Players may hold more than one non-FIFA nationality; Club dissolved during season would shown by grey background.

Foreign Players
Players name in bold indicates the player was registered during the mid-season transfer window.

Semi-finals
Khon Kaen United won 5–2 on aggregate.

Nakhon Pathom United won 4–1 on aggregate.

Finals
''3–3 on aggregate. Khon Kaen United won 4–3 on penalties.''

Top scorers

 * As of 31 March 2021.

Clean sheets

 * As of 24 April 2021.

Attendances by home match played
Source: Thai League Note: Unk.1 Some error of T2 official match report 3 March 2021 (Udon Thani 1–1 Khonkaen United). Unk.2 Some error of T2 official match report 31 March 2021 (Kasetsart 0–3 Nongbua Pitchaya).