List of 2019 Thai League 1 Teams

The 2019 Thai League 1 is the 23rd season of the Thai League 1, the top Thai professional league for association football clubs, since its establishment in 1996, also known as Toyota Thai League due to the sponsorship deal with Toyota Motor Thailand. A total of 16 teams will compete in the league. The season began on 22 February 2019 and is scheduled to conclude on 27 October 2019.

Buriram United are the defending champions, while PTT Rayong, Trat and Chiangmai have entered as the promoted teams from the 2018 Thai League 2.

The 1st transfer window is from 26 November 2018 to 19 February 2019 while the 2nd transfer window is from 24 June 2019 to 19 July 2019.