1997–98 Thailand Division 1 League

The 1997–98 Thailand Division 1 League was its first season. A total of 10 teams participated, with 6 teams relegated from the Thailand Soccer League and 4 teams promoted from the Khǒr Royal Cup.

Member clubs locations
6 clubs relegated from 1996–97 Thailand Soccer League
 * Thailand Tobacco Monopoly
 * Osotsapa
 * Bangkok Bank of Commerce
 * Chula-Raj-Vithi (Rajvithi-Agfatech)
 * Krung Thai Bank
 * Thamrong Thai Samosorn (Singha-Thamrongthai)

4 clubs promoted from 1996 Khǒr Royal Cup
 * Rayong-Rajapruk (Rayong Sport Association)
 * Chonburi-Sannibat-Samut Prakan (Samut Prakan Confederation)
 * Crown Property Bureau
 * Bank for Agriculture (Bank for agriculture and agricultural co-operatives)

Promotion and relegation Playoff
The club that came 9th would play in a relegation / promotion match against the runner-up in the Khǒr Royal Cup.

February 17, 1998

† Chula-Raj-Vithi remain at the Thailand Division 1 League.