The 1997–98 season was the 83rd season of the Isthmian League, which is an English football competition featuring semi-professional and amateur clubs from London, East and South East England. The league consisted of four divisions.
| Competition: | Isthmian League Premier Division |
| Season: | 1997–98 |
| Winners: | Kingstonian |
| Promoted: | Kingstonian |
| Relegated: | Hitchin Town Oxford City Yeading |
| Matches: | 462 |
| Total Goals: | 1343 |
| Highest Attendance: | 2,019 – Kingstonian – Sutton United, (15 November) |
| Attendance: | 206,905 |
| Average Attendance: | 448 (-10.0% to previous season) |
| Prevseason: | 1996–97 |
| Nextseason: | 1998–99 |
The Premier Division consisted of 22 clubs, including 18 clubs from the previous season and four new clubs:
Kingstonian won the division and were promoted to the Football Conference to reach the highest level in the club history. Yeading, Hitchin Town and Oxford City finished bottom of the table and relegated to the First Division.
| Competition: | Isthmian League Division One |
| Season: | 1997–98 |
| Winners: | Aldershot Town |
| Promoted: | Aldershot Town Billericay Town Hampton |
| Relegated: | Abingdon Town Thame United Wokingham Town |
| Matches: | 462 |
| Total Goals: | 1382 |
| Highest Attendance: | 4,289 – Aldershot Town – Berkhamsted Town, (2 May) |
| Attendance: | 142,653 |
| Average Attendance: | 309 (+2.3% to previous season) |
| Prevseason: | 1996–97 |
| Nextseason: | 1998–99 |
Division One consisted of 22 clubs, including 16 clubs from the previous season and six new clubs:Three clubs relegated from the Premier Division:
Three clubs promoted from Division Two:
Before the start of the season Collier Row & Romford F.C. were renamed Romford.
Aldershot Town won the division and were promoted to the Premier Division along with Billericay Town and Hampton. Wokingham Town, Abingdon Town and Thame United relegated to Division Two.
| Competition: | Isthmian League Division Two |
| Season: | 1997–98 |
| Winners: | Canvey Island |
| Promoted: | Braintree Town Canvey Island Wealdstone |
| Relegated: | Cheshunt Egham Town Tilbury |
| Matches: | 462 |
| Total Goals: | 1496 |
| Highest Attendance: | 1,108 – Canvey Island – Braintree Town, (3 January) |
| Attendance: | 78,257 |
| Average Attendance: | 169 (+24.3% to previous season) |
| Prevseason: | 1996–97 |
| Nextseason: | 1998–99 |
Division Two consisted of 22 clubs, including 16 clubs from the previous season and six new clubs:
Three clubs relegated from Division One:
Three clubs promoted from Division Three:
Canvey Island won the division and returned to Division One straight after relegation from it along with Braintree Town and Wealdstone, both achieved the second promotions in two seasons. Tilbury relegated to Division Three along with Egham Town and Abingdon Town.
| Competition: | Isthmian League Division Three |
| Season: | 1997–98 |
| Winners: | Hemel Hempstead |
| Promoted: | Harlow Town Hemel Hempstead Hertford Town |
| Matches: | 380 |
| Total Goals: | 1221 |
| Highest Attendance: | 480 – Hertford Town – Ware, (27 December) |
| Attendance: | 29,119 |
| Average Attendance: | 77 (-31.3% to previous season) |
| Prevseason: | 1996–97 |
| Nextseason: | 1998–99 |
Division Three consisted of 20 clubs, including 14 clubs from the previous season and six new clubs:
Three clubs relegated from Division Two:
Plus:
Hemel Hempstead won the division and returned to Division Two straight after relegation along with Hertford Town and Harlow Town.