 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.He finished the season with eight goals from 30 appearances, as Sutton won the National League South title and therefore promotion into the National League, but missed the latter part of the season due to injury.