| Season: | 1999 |
| Relegated: | Royal Thai Army Bangkok Bank of Commerce |
| League Topscorer: |  Sutee Suksomkit (Thai Farmers Bank) (13) |
| Biggest Home Win: | Royal Thai Air Force 10-0 Bangkok Bank of Commerce Royal Thai Army 6-2 Bangkok Bank of Commerce Thai Farmers Bank 4-0 Bangkok Bank of Commerce |
| Highest Scoring: | Royal Thai Air Force 10-0 Bangkok Bank of Commerce (10 goals) Royal Thai Army 6-2 Bangkok Bank of Commerce (8 goals) |
| Nextseason: | 2000 |
The 1999 Thai Premier League consisted of 12 teams. The bottom club would be relegated to the Thailand Division 1 League. The club that came 11th would play in a relegation / promotion match against the club that came second in the Thailand Division 1 League
Defending Champions Sinthana would enter the next edition of the Asian Club Championship.
The league was also known as the Caltex Premier League.
The club that came 11th would play in a relegation / promotion match against the runner-up in the Thailand Division 1 League
† Royal Thai Army relegated to the Thailand Division 1 League and Royal Thai Navy promoted to the Thai Premier League in next season.
The 27th edition of the Queen's Cup was won by guest side Hanyang University of South Korea. This would be their 7th and final victory in the competition.
Bangkok Bank won and retained the trophy for the second year running, by defeating Osotsapa 2–1. This was Bangkok Bank's 4th victory in the competition.
Sutee Suksomkit - 13 Goals[1] Thai Farmers BankThe league champion was Royal Thai Air Force. It was the team's second title.