1948 Speedway National League
| League | National League Division One | 
|---|---|
| No. of competitors | 7 | 
| Champions | New Cross Rangers | 
| National Trophy | Wembley Lions | 
| Anniversary Cup | Harringay Racers | 
| Riders' champion | Vic Duggan | 
| London Cup | Wembley Lions | 
| Highest average | Vic Duggan | 
| Division/s below | National League (Div 2) National League (Div 3)  | 
The 1948 National League Division One was the 14th season of speedway in the United Kingdom and the third post-war season of the highest tier of motorcycle speedway in Great Britain.