| Club: | Gençlerbirliği |
| Season: | 2020–21 |
| Chrtitle: | President |
| Chairman: | Murat Cavcav |
| Mgrtitle: | Manager |
| Manager: | Mert Nobre (until 10 November 2020) Mustafa Kaplan (until 1 February 2021) Mehmet Altıparmak (until 8 March 2021) Özcan Bizati (from 12 March 2021) |
| Stadium: | Eryaman Stadium |
| League: | Süper Lig |
| League Result: | 20th (relegated) |
| Cup1: | Turkish Cup |
| Cup1 Result: | Fifth round |
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| Prevseason: | 2019–20 |
| Nextseason: | 2021–22 |
The 2020–21 season was the 98th season of Gençlerbirliği S.K. in existence and the club's second consecutive season in the top flight of Turkish football. In addition to the domestic league, Gençlerbirliği participated in the season's edition of the Turkish Cup. The season covers the period from July 2020 to 30 June 2021.
See main article: 2020–21 Süper Lig.
See main article: 2020–21 Turkish Cup.
[2] Players with no appearances not included in the list.
| No. | Pos. | Nat. | Name | Süper Lig | Turkish Cup | Total | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Apps | Goals | Apps | Goals | Apps | Goals | ||||||||||
| 1 | GK | 36 | 0 | 0 | 0 | 36 | 0 | ||||||||
| 2 | DF | 29 | 3 | 0 | 0 | -- | 29 | 3 | |||||||
| 3 | DF | 23 | 2 | 2 | 0 | 25 | 2 | ||||||||
| 4 | DF | 31 | 1 | 1 | 0 | 32 | 1 | ||||||||
| 6 | DF | 25 | 3 | 0 | 0 | 25 | 3 | ||||||||
| 7 | MF | 21 | 0 | 2 | 0 | 23 | 0 | ||||||||
| 8 | MF | 34 | 1 | 1 | 1 | 35 | 2 | ||||||||
| 9 | FW | 24 | 7 | 0 | 0 | 24 | 7 | ||||||||
| 10 | MF | 35 | 4 | 1 | 0 | 36 | 4 | ||||||||
| 11 | MF | 6 | 0 | 0 | 0 | 6 | 0 | ||||||||
| 12 | DF | 6 | 0 | 0 | 0 | 6 | 0 | ||||||||
| 13 | FW | 22 | 2 | 0 | 0 | 22 | 2 | ||||||||
| 14 | DF | 5 | 0 | 0 | 0 | 5 | 0 | ||||||||
| 15 | DF | 23 | 0 | 0 | 0 | 23 | 0 | ||||||||
| 17 | FW | 20 | 1 | 1 | 0 | 21 | 1 | ||||||||
| 19 | MF | 16 | 0 | 1 | 0 | 17 | 0 | ||||||||
| 21 | MF | 35 | 4 | 0 | 0 | 35 | 4 | ||||||||
| 23 | MF | 36 | 6 | 0 | 0 | 36 | 6 | ||||||||
| 26 | FW | 15 | 0 | 2 | 0 | 17 | 0 | ||||||||
| 27 | DF | 12 | 0 | 0 | 0 | 12 | 0 | ||||||||
| 30 | MF | 10 | 0 | 0 | 0 | 10 | 0 | ||||||||
| 33 | FW | 30 | 3 | 0 | 0 | 30 | 3 | ||||||||
| 39 | DF | 33 | 0 | 0 | 0 | 33 | 0 | ||||||||
| 44 | GK | 4 | 0 | 1 | 0 | 5 | 0 | ||||||||
| 55 | DF | 1 | 0 | 1 | 0 | 2 | 0 | ||||||||
| 63 | MF | 9 | 0 | 1 | 0 | 10 | 0 | ||||||||
| 66 | MF | 0 | 0 | 1 | 0 | 1 | 0 | ||||||||
| 88 | MF | 30 | 1 | 1 | 0 | 31 | 1 | ||||||||
| 91 | FW | 16 | 2 | 0 | 0 | 16 | 2 | ||||||||
| 93 | GK | 1 | 0 | 0 | 0 | 1 | 0 | ||||||||
| Players on loan who featured during season | |||||||||||||||
| 16 | GK | 0 | 0 | 1 | 0 | 1 | 0 | ||||||||
| 22 | DF | 0 | 0 | 2 | 0 | 2 | 0 | ||||||||
| 28 | FW |  | 0 | 0 | 2 | 0 | 2 | 0 | |||||||
| 77 | MF | 6 | 0 | 1 | 0 | 6 | 0 | ||||||||
| Players who left but featured during season | |||||||||||||||
| 5 | MF | 13 | 3 | 0 | 0 | 13 | 3 | ||||||||