The 2012–13 Professional Development League 1 (referred to as the Barclays Under 21 Premier League for sponsorship reasons) is the inaugural season of the Professional Development League 1. There are 23 participating teams in the 2012–13 Professional Development League. They are split into three groups. After a double round-robin, teams are divided into three new groups based on league standing in the first half of the season, to ensure better-matched games in the second half of the season. At the end of the second half of the season, the winners of the two "Qualification groups" will play off for the right to contest a knock-out semi-final against the winner of the "Elite group", while the second and third placed teams of the Elite group also contest a semi-final. The winners of these semi-finals will play a final to determine the overall winner of the Professional Development League for the season.