The 2017–18 season was Colchester United's 81st season in their history and their second successive season competing in League Two. Along with competing in League Two, the club will also participate in the FA Cup, EFL Cup and EFL Trophy. Colchester made a first round exit in the EFL Cup for the seventh consecutive season, narrowly losing out to Aston Villa, while in the FA Cup, they were eliminated by non-League outfit Oxford City in the first round. In the EFL Trophy, Colchester were knocked out at the group stage for the second season running.