| Club: | 1. FC Köln |
| Season: | 2020–21 |
| Chrtitle: | President |
| Chairman: | Werner Wolf |
| Mgrtitle: | Head coach |
| Manager: | Markus Gisdol (until 11 April) Friedhelm Funkel (from 12 April) |
| Stadium: | RheinEnergieStadion |
| League: | Bundesliga |
| League Result: | 16th (play-off winners) |
| Cup1: | DFB-Pokal |
| Cup1 Result: | Round of 16 |
| League Topscorer: | Elvis Rexhbeçaj (5) |
| Season Topscorer: | Elvis Rexhbeçaj (7) |
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| Prevseason: | 2019–20 |
| Nextseason: | 2021–22 |
The 2020–21 season was the 73rd season in the existence of 1. FC Köln and the club's second consecutive season in the top flight of German football. In addition to the domestic league, 1. FC Köln participated in this season's edition of the DFB-Pokal. The season covered the period from 1 July 2020 to 30 June 2021.
| scope=col | Player | Transferred from | scope=col; style="width: 65px;" | Fee' | scope=col | Date | scope=col | Source | ||
|---|---|---|---|---|---|---|---|---|---|---|
| 16 | Hannover 96 | Loan | [1] | |||||||
| 9 | Union Berlin | €6,500,000 | [2] | |||||||
| 18 | Hertha BSC | €7,000,000 | [3] | |||||||
| 7 | Valmieras | Loan | [4] | |||||||
| 15 | PAOK | €3,300,000 | [5] | |||||||
| 31 | Borussia Dortmund | Loan | [6] | |||||||
| 43 |  Club Brugge | Loan | [7] | |||||||
| 13 | Crystal Palace | Free | [8] |
| scope=col | Player | Transferred to | scope=col; style="width: 65px;" | Fee | scope=col | Date | scope=col | Source | ||
|---|---|---|---|---|---|---|---|---|---|---|
| 8 | Antwerp | Loan | ||||||||
| 18 | Retired | |||||||||
| 36 | Holstein Kiel | Loan | [9] | |||||||
| 28 | Waldhof Mannheim | Free | [10] | |||||||
| Vitória de Guimarães | Loan | [11] | ||||||||
| 11 | Hannover 96 | Loan | [12] | |||||||
 MFK Karviná | Loan | |||||||||
| C.D. Nacional | Loan | [13] | ||||||||
| 31 |  Nashville SC | Free | [14] | |||||||
| 7 | Viktoria Köln | Loan | [15] | |||||||
| 9 | Hamburger SV | Free | [16] | |||||||
| 3 | FC Zürich | Loan | [17] | |||||||
| 15 | Hertha BSC | €15,000,000 | [18] | |||||||
| 13 | FC Luzern | Loan | [19] | |||||||
| 17 | SV Darmstadt 98 | Free | [20] | |||||||
| 30 | Mutual contract termination | [21] | ||||||||
| 27 |  Saint-Étienne | Loan | [22] |
See main article: 2020–21 Bundesliga.
The league fixtures were announced on 7 August 2020.[23]
As a result of their 16th-place finish in the regular season, the club qualified for the play-off match with the third-place team in the 2020–21 2. Bundesliga to determine whether the club would remain in the 2021–22 Bundesliga.
See main article: 2020–21 DFB-Pokal.
|-! colspan=14 style=background:#dcdcdc; text-align:center| Goalkeepers|-! colspan=14 style=background:#dcdcdc; text-align:center| Defenders|-! colspan=14 style=background:#dcdcdc; text-align:center| Midfielders |-! colspan=14 style=background:#dcdcdc; text-align:center| Forwards|-! colspan=14 style=background:#dcdcdc; text-align:center| Players transferred out during the season
| width=15 | width=15 | width=15 | width=15 | width=145 | Name | width=80 | Bundesliga | width=80 | DFB-Pokal | width=80 | Relegation play-offs | width=80 | Total | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | MF | 7 | Elvis Rexhbeçaj | 5 | 2 | 0 | 7 | ||||||||||
| MF | 10 |  | Ondrej Duda | 7 | 0 | 0 | 7 | ||||||||||
| 3 | MF | 28 |  | Ellyes Skhiri | 5 | 0 | 1 | 6 | |||||||||
| 4 | FW | 9 |  | Sebastian Andersson | 3 | 0 | 2 | 5 | |||||||||
| MF | 14 | Jonas Hector | 3 | 1 | 1 | 5 | |||||||||||
| 6 | DF | 5 | Rafael Czichos | 1 | 1 | 1 | 3 | ||||||||||
| MF | 24 | Dominick Drexler | 2 | 1 | 0 | 3 | |||||||||||
| 8 | DF | 8 | Ismail Jakobs | 1 | 1 | 0 | 2 | ||||||||||
| MF | 29 | Jan Thielmann | 2 | 0 | 0 | 2 | |||||||||||
| MF | 31 | Marius Wolf | 2 | 0 | 0 | 2 | |||||||||||
| 11 | MF | 11 | Florian Kainz | 1 | 0 | 0 | 1 | ||||||||||
| MF | 21 | Salih Özcan | 0 | 1 | 0 | 1 | |||||||||||
| FW | 27 | | Anthony Modeste | 1 | 0 | 0 | 1 | ||||||||||
| DF | 33 | | Sebastiaan Bornauw | 1 | 0 | 0 | 1 | ||||||||||
| FW | 43 |  | Emmanuel Dennis | 0 | 1 | 0 | 1 | ||||||||||
| Own goals | 1 | 0 | 0 | 1 | |||||||||||||
| Totals | 34 | 9 | 5 | 48 | |||||||||||||