The 1899–1900 Northern Football League season was the eleventh in the history of the Northern Football League, a football competition in Northern England.
| Competition: | Northern League |
| Season: | 1899–1900 |
| Prevseason: | 1898–99 |
| Nextseason: | 1900–01 |
| Competition: | Northern League Division One |
| Season: | 1899–1900 |
| Winners: | Darlington |
| Matches: | 72 |
| Total Goals: | 243 |
The division featured 7 clubs which competed in the last season, along with two new clubs, promoted from last seasons's Division Two:
| Competition: | Northern League Division Two |
| Season: | 1899–1900 |
| Winners: | Whitby |
| Matches: | 56 |
| Total Goals: | 232 |
The division featured 7 clubs which competed in the last season, along with three new clubs: