2020–21 Serie D
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.
Changes from 2019–20
A total 166 clubs were admitted to the season, including the new incarnation of former Serie A club Siena.Teams
The composition of the league will involve nine divisions, grouped geographically and named alphabetically.Teams relegated from Serie C
A total of eight teams from the 2019–20 Serie C were admitted: Siena, Picerno and the relegated teams Pianese, Gozzano, Arzignano, Rimini, Rende and Rieti.Teams promoted from Eccellenza
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.;Abruzzo
- Castelnuovo Vomano
- Molfetta
- Lavello
- Rotonda
;Campania
- Afragolese
- Puteolana
- Santa Maria Cilento
- Bagnolese
- Corticella
- Marignanese
- Manzanese
- Insieme Ausonia
- Montespaccato
;Lombardy
- Busto 81
- Casatese
- Telgate
- Vis Nova Giussano
;Molise
- Comprensorio Vairano
- Tre Pini Matese
;Sardinia
- Carbonia
- Dattilo Noir
- Paternò
- Sant'Agata
;Tuscany
- Badesse
- Pro Livorno
- Sinalunghese
- Tiferno Lerchi
- Sona
- Union San Giorgio Sedico
- merged with Città di Varese
- merged with Grumellese under the new denomination of Real Calepina
- merged with Tre Pini Matese under the new denomination FC Matese