The 2018–19 HT Premijer liga was the 28th season of the HT Premijer liga, the highest professional basketball league in Croatia.

As in the previous season, all participants in Premijer liga including teams that play ABA League joined the regular season.

It was played with a double round-robin format where the eight first qualified teams joined the playoffs, while the penultimate will be play relegation playoffs and last qualified one was relegated.

Teams that play in the 2018–19 Second Adriatic League Quarterfinals and semifinals will be played in a best-of-three-games format, while the finals in a best-of-five one.

As of the 2018–19 season, team who lost the 2018–19 First League final and the 11th placed team of the 2018–19 Premijer liga season will play in the Qualifiers for a spot in the 2019–20 Premijer liga season.