| Club: | ADO Den Haag |
| Season: | 2020–21 |
| Chrtitle: | Chairman |
| Chairman: | Ben Knüppe |
| Mgrtitle: | Head coach |
| Manager: | Aleksandar Ranković |
| Stadium: | Cars Jeans Stadion |
| League: | Eredivisie |
| League Result: | 18th (relegated) |
| Cup1: | KNVB Cup |
| Cup1 Result: | Round of 16 |
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| Prevseason: | 2019–20 |
| Nextseason: | 2021–22 |
The 2020–21 ADO Den Haag season was the club's 116th season in existence and the 13th consecutive season in the top flight of Dutch football. In addition to the domestic league, ADO Den Haag participated in this season's edition of the KNVB Cup. The season covered the period from 1 July 2020 to 30 June 2021.
See main article: 2020–21 Eredivisie.
The league fixtures were announced on 24 July 2020.[1]
See main article: 2020–21 KNVB Cup.