Maguire and John Higgins lost in the final of the 2015 Snooker World Cup to Chinese youngsters Zhou Yuelong and Yan Bingtao. He reached the semi-finals of the first ranking event of the year by thrashing Judd Trump 5–1 at the Australian Goldfields Open, but he lost 6–1 to Martin Gould. Maguire began his fourth round match against Neil Robertson with a 118 break, but it was the only frame he could win in a 6–1 defeat. He was knocked out in the quarter-finals of the German Masters 5–1 by Graeme Dott and the first round of both the Welsh Open (4–3 to Martin O'Donnell) and the World Grand Prix (4–0 to Higgins). Maguire failed to qualify for the PTC Finals after finishing 42nd on the European Order of Merit. This meant that he needed results to go his way and have a strong run at the China Open to avoid having to qualify for the World Championship. Four wins to the semi-finals saw Maguire accomplish this, but he was whitewashed 6–0 by Trump. Despite achieving automatic qualification for the World Championship, Maguire stated that he felt embarrassed at how he was unable to motivate himself for the event after losing 10–7 to Alan McManus in the first round. He finished a campaign outside of the top 16 for the first time since 2004, as he was 18th.