2015 Thai League Division 1 (known as Yamaha League-1 for sponsorship reasons) was the 18th season of the League since its establishment in 1997. It is the feeder league for the Thai Premier League. A total of 20 teams competed in the league this season.
Promoted to Thai Premier League
Relegated to Regional League Division 2
Relegated from Thai Premier League
Promoted from Regional League Division 2
<small>Note: Flags indicate national team as has been defined under FIFA eligibility rules. Players may hold more than one non-FIFA nationality.</small>
The number of foreign players is restricted to five per TPL team, including a slot for a player from AFC countries. A team can use four foreign players on the field in each game, including at least one player from the AFC country.
<onlyinclude></onlyinclude>