| Club: | Chelsea |
| Season: | 1938–39 |
| Manager: | Leslie Knighton |
| Chairman: | Lt. Col Charles Chrisp |
| Stadium: | Stamford Bridge |
| League: | First Division |
| League Result: | 20th |
| Cup1: | FA Cup |
| Cup1 Result: | Quarter-finals |
| League Topscorer: | Joe Payne (17) |
| Season Topscorer: | Joe Payne (19) |
| Largest Win: | 5–1 v Grimsby Town |
| Largest Loss: | 1–6 v Stoke City |
| Highest Attendance: | |
| Lowest Attendance: | |
| Pattern B1: | _chelsea1907h |
| Pattern So1: | _2bluestripes |
| Leftarm1: | 0000FF |
| Body1: | FFFFFF |
| Rightarm1: | 0000FF |
| Shorts1: | ffffFF |
| Socks1: | 000000 |
| Pattern So2: | _2bluestripes |
| Leftarm2: | FF0000 |
| Body2: | FF0000 |
| Rightarm2: | FF0000 |
| Shorts2: | FFFFFF |
| Socks2: | 000000 |
| Prevseason: | 1937–38 |
| Nextseason: | 1939–40 |
The 1938–39 season was Chelsea Football Club's thirtieth competitive season. It was the last completed season of competitive football in England before the outbreak of the Second World War. The club finished the season 20th in The First Division, one point above the relegation zone. They also reached the quarter-finals of the FA Cup, a run which ended with a 1–0 home loss to Grimsby Town.