Thai League 1 (Thailand) 2026/27

Thai League 1 stands as the top-flight professional football league in Thailand, organized by Thai League Co., Ltd., a subsidiary of the Football Association of Thailand. While the national championship was previously determined by the Kor Royal Cup, this competition has operated under its current structure since its founding in 1996, initially as the Thailand Soccer League. The league underwent significant structural changes, including a 2007 merger with the SAT-run Provincial League and major reforms in 2009 requiring clubs to separate from parent organizations to meet AFC licensing standards. In 2017, it was rebranded from the Thai Premier League to Thai League 1 to foster an international identity.

The season format is a double round-robin, where each team plays every other team twice, totaling 30 matches per club. There are no playoffs for the league title, as the champion is determined by the final standings. Promotion and relegation connect the league to Thai League 2, with the bottom three teams in Thai League 1 directly relegated. From Thai League 2, the champion and runner-up are directly promoted, while teams ranked 3rd to 6th enter a play-off tournament for the final spot. A distinctive feature of the competition is its foreign player quota system. For the 2026–27 season, the league plans to unify this into a single foreign player quota of 10 registered players, with a maximum of 7 on the pitch.

Buriram United is the most successful club in the league's history, holding the record for the most titles. As of the conclusion of the 2024–25 season, Buriram United is the reigning champion, having won their 11th title that season. Winning the Thai League 1 is considered the highest domestic achievement, granting qualification to the AFC Champions League Elite. The competition currently features 16 clubs, distinguishing it from other domestic competitions like the Thai FA Cup and Thai League Cup, which are knockout tournaments.