The 1939–40 Northern Football League season was the 47th in the history of the Northern Football League, a football competition in Northern England.
| Competition: | Northern League |
| Season: | 1939–40 |
| Winners: | Shildon |
| Matches: | 30 |
| Total Goals: | 173 |
| Prevseason: | 1938–39 |
| Nextseason: | 1945–46 |
The league originally featured 12 clubs which competed in the last season, along with two new clubs:
The initial competition was abandoned on 16 December 1939 after Whitby United, Evenwood Town, Brandon Social,[1] Billingham, Cockfield, and Ferryhill Athletic resigned from the league between 30 September and 16 December. The remaining eight clubs agreed to begin a new competition beginning on 1 January 1940.