Dinamo Zagreb were the defending champions, having won their seventh consecutive title in 2011–12.
The league was contested by twelve teams, four fewer than in the previous season, with each club playing every other club three times for a total of 33 rounds (last time the system was used in the 2008–09 season).
On 13 April 2012, Croatian Football Federation announced that the first stage of licensing procedure for 2012–13 season was completed.
[2] On 15 May 2012, it was announced that all remaining Prva HNL clubs from the previous season were granted top level license, except for Šibenik, Karlovac and Varaždin.
If that wasn't the case, Inter Zaprešić and Rijeka would have needed to play a two-legged play-off match to decide who gets relegated since they were equal on all of the tiebreakers.