Despite having a higher average (98.91) and higher checkout percentage (60%) than his opponent Michael Smith in the first round of the 2015 World Championship, Suljović lost 3–1 with each set going to a deciding leg. His average was the highest of all 32 first round losers and the fifth highest of all 72 players. Suljović and Rodriguez were eliminated in the last 16 of the World Cup for the second year in a row, this time to Germany. Suljović came from 5–2 down against Terry Jenkins in the opening round of the World Matchplay to win 11–9 and then enjoyed a big win by taking out reigning world champion Gary Anderson 13–9. In his third major PDC quarter-final, Suljović was 12–5 down to James Wade, but responded to trail just 13–11. He missed one dart at double 14 in the next leg to reduce the gap to a single leg and instead went on to be defeated 16–11. He exacted revenge over Wade in the next major by beating him 2–1 in sets in the opening round of the World Grand Prix. Suljović was a set down but won six unanswered legs aided with checkouts of 148 and 129 to eliminate the two-time winner of the event. His form in the major events this year continued as he progressed to his third successive quarter-final with a 3–0 whitewash over Simon Whitlock. Vincent van der Voort missed 11 darts to take a 2–0 lead and Suljović responded by taking nine consecutive legs and wrapped up the match with a 170 finish in a win which he described as the best moment of his career. Suljović fought for a narrow 2–1 lead in his first major semi-final, but Robert Thornton won three sets in a row to end his tournament with a 4–2 defeat.