The 2012–13 First League of the Republika Srpska is the eighteenth season of the First League of the Republika Srpska, the second tier football league of Bosnia and Herzegovina, since its original establishment and the eleventh as a second-tier league. It will begin on 11 August 2012 and end on 25 May 2013; a winter break where no matches are played will be in effect between 3 November 2012 and 9 March 2013. Radnik were the last champions, having won their third championship title in the 2011–12 season and earning a promotion to Premier League of Bosnia and Herzegovina. This year Mladost Velika Obarska won the championship, the first time they won the First League of the Republika Srpska.
Fourteen clubs are participating in this session, ten returning from the previous session, one relegated from Premier League of Bosnia and Herzegovina, two promoted from two regional Second League of the Republika Srpska and one as a replacement for Crvena Zemlja who withdraw from the competition due to financial difficulties.