| Club: | FC Basel |
| Season: | 1939–40 |
| Chairman: | Albert Besse |
| Mgrtitle: | First team coach |
| Manager: | Walter Dietrich Max Galler |
| Stdtitle: | Ground |
| Stadium: | Landhof, Basel |
| League: | 1. Liga Group 3 |
| League Result: | Winners |
| League2: | 1. Liga play-off |
| League2 Result: | Winners |
| Cup1: | Swiss Cup |
| Cup1 Result: | Round 4 |
| League Topscorer: | August Ibach (19) |
| Season Topscorer: | August Ibach (20) |
| Highest Attendance: | 2,000 on 31 March 1940 vs Aarau |
| Lowest Attendance: | 500 on 18 February 1940 vs Concordia Basel and on 23 June 1940 vs Solothurn |
| Average Attendance: | 1,266 |
| Prevseason: | 1938–39 |
The FC Basel 1939–40 season was the forty-seventh season since the club's foundation on 15 November 1893. FC Basel played their home games in the Landhof in the district Wettstein in Kleinbasel. Albert Besse was the club's new chairman. He took over from Emil Junker at the AGM on 15 July 1939.
After being relegated last season for the first time in the club's history, Basel played this season in the newly reorganized 1.Liga. Due to the outbreak of World War II on 1 September 1939 the start of the Swiss football championship was postponed until 22 October and the 1. Liga postponed until December. The 1939–40 Nationalliga was played as "Championnat Suisse de Mobilisation" due to the war and the 1. Liga divided into five regional zones. There was to be no promotion and no relegation. Basel were allocated to . Liga group 3 (North-West Switzerland) together with Solothurn, Aarau, Concordia Basel and FC Birsfelden. The group was played in three round-robins.
Player-manager Fernand Jaccard had left the club after the relegation season to join FC Locarno. The former players Walter Dietrich and Max Galler took over as team co-managers. Basel played a good season, in total including test matches they played 29 games, winning 22, drawing three and suffering four defeats. In total they scored 98 goals conceding 50.[1]
After winning their four test games in October, Basel started the season well in December winning the first seven matches straight off before suffering their first defeat at the beginning of April. At the end of the group stage Basel had won nine games drawn two and were defeated just once and with 20 points were five points above second placed Aarau. Basel advanced to the play-off stage. In the semi-final they won the round-robin against group four winners SC Brühl St. Gallen and group five winners AC Bellinzona. Basel became 1. Liga champions winning the best of three final against Fribourg.[2] August Ibach was team top league goal scorer with 19 goals, Fritz Schmidlin, Hermann Suter and Werner Wenk each scored five times.
In the Swiss Cup Basel started with a victory in the 2nd principal round away against lower tier SC Zofingen. In the next round they were again drawn away from home against lower tier SC Schöftland. This was won 4–1. In the next round Basel played in the Landhof against Aarau but were defeated and knocked out of the competition.[3]
The following is the list of the Basel first team squad during the season 1939–40. The list includes players that were in the squad the day the season started on 1 October 1939 but subsequently left the club after that date.