The 2015 USL Premier Development League season was the 21st season of the PDL and consisted of 63 teams. The regular season began on May 2 and ended on July 19. The Michigan Bucks were the defending champions and posted the best overall record in the League; however, they were defeated by K-W United FC in the Central Conference finals. K-W United went on to win the league championship by defeating the Seattle Sounders FC U-23 1-0 in the semi-finals and in high scoring final they overcame the New York Red Bulls U-23 4-3. 63 clubs competed in the semi-professional soccer leagues.