| Competition: | Serie D |
| Season: | 2020–21 |
| Dates: | 27 September 2020 – 10 July 2021 |
| Winners: | not awarded |
| Promoted: | Seregno Trento Fiorenzuola Montevarchi Campobasso Monterosi Taranto ACR Messina Picerno (admitted) Siena (repechage) Latina (repechage) Fidelis Andria (repechage) |
| Relegated: | To Eccellenza: Scanzorosciate Virtus Bolzano Chions Corticella Grassina Sinalunghese Porto Sant'Elpidio Olympia Agnonese Puteolana Marina di Ragusa Roccella Disbanded: NibionnOggiono Real Giulianova Savoia Dattilo |
| Prevseason: | 2019–20 |
| Nextseason: | 2021–22 |
The 2020–21 Serie D was the seventy-third edition of the top level Italian non-professional football championship. It represents the fourth tier in the Italian football league system.
A total 166 clubs were admitted to the season, including the new incarnation of former Serie A club Siena.
The composition of the league will involve nine divisions, grouped geographically and named alphabetically.
A total of eight teams from the 2019–20 Serie C were admitted: Siena (phoenix club, admitted after the previous club's incarnation did not apply for membership), Picerno (relegated by office due to match-fixing) and the relegated teams Pianese, Gozzano, Arzignano, Rimini, Rende and Rieti.
Due to the COVID-19 related suspension of all amateur sports leagues in Italy, promotions were picked explicitly by the Italian Football Federation based on the leagues' provisional standings at the premature conclusion of the season. No promotion playoffs were held, nor was the final phase of the Coppa Italia Dilettanti (whose winning team is normally automatically admitted into Serie D).
Due to the second wave of the COVID-19 pandemic in Italy, the Lega Nazionale Dilettanti, who is responsible for the organization of the league, decided on 5 November 2020 to suspend the regular Serie D programme until 29 November, instead using this prolonged break to reschedule all games that could not be played due to COVID-19 related health concerns.[1]