| Club: | İstanbul Başakşehir |
| Season: | 2020–21 |
| Chrtitle: | President |
| Chairman: | Göksel Gümüşdağ |
| Mgrtitle: | Head coach |
| Manager: | Okan Buruk (until 29 January) Aykut Kocaman (from 1 February) |
| Stadium: | Başakşehir Fatih Terim Stadium |
| League: | Süper Lig |
| League Result: | 12th |
| Cup1: | Turkish Cup |
| Cup1 Result: | Semi-finals |
| Cup2: | Turkish Super Cup |
| Cup2 Result: | Runners-up |
| Cup3: | UEFA Champions League |
| Cup3 Result: | Group stage |
| League Topscorer: | Fredrik Gulbrandsen (7) |
| Season Topscorer: | Fredrik Gulbrandsen (11) |
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| Prevseason: | 2019–20 |
| Nextseason: | 2021–22 |
The 2020–21 season was the 31st season in existence of İstanbul Başakşehir and the seventh consecutive season in the top flight of Turkish football, the Süper Lig. In addition to the domestic league, Başakşehir participated in this season's editions of the Turkish Cup, the Turkish Super Cup and the UEFA Champions League. The season covered the period from 5 August 2020 to 30 June 2021.
| scope=col | Player | Transferred from | scope=col; style="width: 65px;" | Fee | scope=col | Date | scope=col | Source | ||
|---|---|---|---|---|---|---|---|---|---|---|
| 11 | Monaco | Undisclosed | [2] |
| scope=col | Player | Transferred to | scope=col; style="width: 65px;" | Fee | scope=col | Date | scope=col | Source | ||
|---|---|---|---|---|---|---|---|---|---|---|
| 3 | Servette | Free | [3] |
See main article: 2020–21 Süper Lig.
See main article: 2020–21 Turkish Cup.
See main article: 2020 Turkish Super Cup.
See main article: 2020–21 UEFA Champions League.
The group stage draw was held on 1 October 2020.[4]
| width=15 | width=15 | width=15 | width=15 | width=145 | Name | width=100 | Süper Lig | width=100 | Turkish Cup | width=130 | Turkish Super Cup | width=140 | Champions League | width=100 | Total | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 22 | FW |  | Fredrik Gulbrandsen | 6 | 4 | 0 | 0 | 10 | ||||||||||
| 2 | 7 | MF |  | Edin Višća | 5 | 0 | 0 | 1 | 6 | ||||||||||
| 17 | MF |  | İrfan Kahveci | 2 | 1 | 0 | 3 | 6 | |||||||||||
| 19 | FW |  | Demba Ba | 2 | 2 | 1 | 1 | 6 | |||||||||||
| 5 | 8 | MF |  | Danijel Aleksić | 2 | 2 | 0 | 0 | 4 | ||||||||||
| 6 | 5 | MF | | Mehmet Topal | 2 | 0 | 0 | 1 | 3 | ||||||||||
| 7 | 11 | MF |  | Nacer Chadli | 1 | 1 | 0 | 0 | 2 | ||||||||||
| 20 | MF |  | Giuliano | 2 | 0 | 0 | 0 | 2 | |||||||||||
| 23 | MF | | Deniz Türüç | 1 | 0 | 0 | 1 | 2 | |||||||||||
| 27 | FW |  | Enzo Crivelli | 2 | 0 | 0 | 0 | 2 | |||||||||||
| 11 | 9 | FW | Junior Fernandes | 0 | 1 | 0 | 0 | 1 | |||||||||||
| 21 | MF | | Mahmut Tekdemir | 1 | 0 | 0 | 0 | 1 | |||||||||||
| 24 | DF | | Ravil Tagir | 0 | 1 | 0 | 0 | 1 | |||||||||||
| 29 | MF | | Kerim Frei | 0 | 1 | 0 | 0 | 1 | |||||||||||
| Own goals | 2 | 1 | 0 | 0 | 3 | ||||||||||||||
| Totals | 28 | 14 | 1 | 7 | 50 | ||||||||||||||