The 1890–91 Northern Football League season was the second in the history of the Northern Football League, a football competition in Northern England.
| Competition: | Northern League |
| Season: | 1890–91 |
| Winners: | Middlesbrough Ironopolis |
| Matches: | 56 |
| Total Goals: | 233 |
| Prevseason: | 1889–90 |
| Nextseason: | 1891–92 |
The league featured 6 clubs which competed in the last season, along with two new clubs: