Elections to Colchester Borough Council were held on 6 May 2021. They were originally planned for 7 May 2020, but postponed until 2021 due to the COVID-19 pandemic. Seventeen members of the council (one-third of the whole) were up for election, one from each of the 17 wards. There were also two additional by-elections in Prettygate and Lexden & Braiswick wards, bringing the total number of elected members to nineteen.