Thai League 2
| Organising body | Thai League Co., Ltd. |
|---|---|
| Founded | 1997 |
| Country | Thailand |
| Confederation | AFC |
| Number of clubs | 18 |
| Level on pyramid | 2 |
| Promotion to | Thai League 1 |
| Relegation to | Thai League 3 |
| Domestic cup | Thai FA Cup |
| League cup | Thai League Cup |
| Current champions | Chonburi (1st title) (2024–25) |
| Most championships | Police United (4 titles) |
| Website | thaileague.co.th/t2 |
| Current: 2025–26 Thai League 2 | |
Thai League 2 (Thai: ไทยลีก 2), commonly known as the T2, formally called Thai Division 1 League, is the second-tier professional league in the Thai football league system. Seasons typically run from August to May, with each team playing 34 games : two against each other team, one home and one away. It is sponsored by BYD Auto and therefore officially known as the BYD Seal 5 League II. Champion, runner up and teams ranked 3rd – 6th qualified in play off for last spot in top tier promoted to Thai League 1 at the end of the season, whilst three are relegated to Thai League 3.