The 1909–10 Northern Football League season was the 21st in the history of the Northern Football League, a football competition in Northern England.
| Competition: | Northern League |
| Season: | 1909–10 |
| Winners: | Bishop Auckland |
| Matches: | 132 |
| Total Goals: | 518 |
| Prevseason: | 1908–09 |
| Nextseason: | 1910–11 |
The league featured 11 clubs which competed in the last season, along with one new club: