Hamilton met Peter Wright in the third round of the 2015 World Championship and was thrashed 4–0. He lost 9–8 to Kim Huybrechts in the fourth round of the UK Open. After beating Raymond van Barneveld 10–7 in the opening round of the World Matchplay, Hamilton described his play over the last six months as horrible. He went on to lose 13–6 to Phil Taylor in the second round and, after dropping out of the top 16 on the Order of Merit, he failed to qualify for any of the remaining major events in 2015.