The Thai League 1, often referred to as T1, is the highest level of the Thai football league system. Contested by 16 clubs, it operates on a system of promotion and relegation with Thai League 2. Seasons typically run from August to May, with each team playing 30 games: two against each other team, one home and one away. It is sponsored by Toyota Motor Thailand and therefore officially known as the Hilux Revo Thai League. In the Thai League, most games are played on Saturday and Sunday evenings, with occasionally played on Wednesday and Friday evening fixtures.

Thai League 2, commonly known as the T2, formally called Thai Division 1 League, is the second-tier professional league in the Thai football league system. The top 3 are promoted to Thai League 1 at the end of the season, whilst four are relegated to Thai League 3.