The National Development League 2021 is the third tier/division of British speedway for the 2021 season.[1]
Due to pressures caused by the COVID-19 pandemic it was decided that the league would be decided by the final table standings only, with no playoffs being held. For the same reason no Knockout Cup would be held.[2]
Newcastle Gems had started the season but dropped out after in June after a couple of fixtures due to financial difficulties. This was followed on 26 August by the Eastbourne Seagulls after parent club, the Eastbourne Eagles withdrew from the league because of financial problems. Their results were expunged.[5]Mildenhall Fen Tigers won their fourth Division 3 title since 2003.[6][7][8]