The 1989–90 Northern Football League season was the 92nd in the history of Northern Football League, a football competition in England.[1]
| Competition: | Northern Football League Division One |
| Season: | 1989–90 |
| Winners: | Billingham Synthonia |
| Relegated: | Billingham Town Easington Colliery |
| Matches: | 380 |
| Total Goals: | 1221 |
| Prevseason: | 1988–89 |
| Nextseason: | 1990–91 |
Division One featured 17 clubs which competed in the division last season, along with three new clubs, promoted from Division Two:
| Competition: | Northern Football League Division Two |
| Season: | 1989–90 |
| Winners: | Murton |
| Promoted: | Murton Northallerton Town Peterlee Newtown |
| Matches: | 380 |
| Total Goals: | 1189 |
| Prevseason: | 1988–89 |
| Nextseason: | 1990–91 |
Division Two featured 17 clubs which competed in the division last season, along with three new clubs.