| 1940 Cork Senior Football Championship | |
| Teams: | 17 |
| Dates: | 31 March 1940 – 15 September 1940 |
| Champions: | Beara |
| Count: | 4 |
| Champions Captain: | D. O'Sullivan |
| Runners-Up: | Millstreet |
| Matches: | 15 |
| Goals: | 56 |
| Points: | 146 |
| Previous Year: | 1939 |
| Previous Tournament: | 1939 Cork Senior Football Championship |
| Next Year: | 1941 |
| Next Tournament: | 1941 Cork Senior Football Championship |
The 1940 Cork Senior Football Championship was the 52nd staging of the Cork Senior Football Championship since its establishment by the Cork County Board in 1887. The draw for the opening round fixtures took place on 28 January 1940. The championship began on 31 March 1940 and ended on 15 September 1940.
Clonakilty were the defending champions, however, they were beaten by Beara at the quarter-final stage.
On 15 September 1940, Beara won the championship following a 2–08 to 1–07 defeat of Millstreet in the final at Skibbereen Town Park.[1] This was their fourth championship title overall and their first title since 1934.