After breaking into the top 32 on the Order of Merit during 2016, it meant Cullen was a seeded player at the World Championship for the first time in his career. He beat Corey Cadby 3–1 in the first round to pick up his first-ever win at the tournament at the seventh time of asking. Cullen averaged 100.88, but went on to lose 4–0 to two-time winner of the event Adrian Lewis in the next round.