Handball club Zagreb is a Croatian handball club from Zagreb, founded in 1922.

In its exceptionally rich history of trophies, the Zagreb handball club won 10 Yugoslav championship titles, and its dominance continued in Croatia, where Zagreb handball players celebrated in 31 editions of the national championship. In only one edition, and it was in that unfortunate year of 2020, the championship was not completed due to the global pandemic of the corona virus. In the former Yugoslavia, the Zagreb team won the Cup back in 1962 and then again in 1991, while in Croatia they did it again 29 times.

Zagreb handball club achieved its greatest European success twice in 1992 and 1993, when it won the title of champion of the Old Continent. In as many as four subsequent finals (1995, 1997, 1998, 1999), Zagreb lost the European Champions League, but despite this, it remained one of the most trophy-winning clubs in Europe. The European Super Cup was won in 1993, and the regional SEHA Gazprom League in 2012. Also, the best Croatian handball players played in the final of the regional competition on three other occasions.

With 76 major trophies won in its history, RK Zagreb is the most trophy-winning Croatian handball and sports club in general. RK Zagreb plays its home matches in Arena Zagreb.