 McAllister signed for National League South club Sutton United prior to the start of 2015–16.He debuted on the opening day of the season in a 2–0 defeat at home to Maidstone United.McAllister scored his first goal for Sutton on 5 September 2015 in a 2–2 draw at home to Concord Rangers, and this was followed up with a goal in the following match, a 1–0 victory at home to Gosport Borough.