2012 Thai League Division 1 (known as Yamaha League 1 for sponsorship reasons) is the 15th season of the League since its establishment in 1997.

It is the feeder league for the Thai Premier League.

A total of 18 teams will compete in the league this season.

Promoted to 2012 Thai Premier League Relegated to Regional League Division 2 Relegated from Thai Premier League Promoted from Regional League Division 2 Thupatemee Stadium 25,000

Updated to games played on 27 Oct 2012Source: Thai Division 1 LeagueNotes:† Team played previous season in Division 2 League.