League of Communists of Croatia (Serbo-Croatian: Savez komunista Hrvatske, SKH) was the Croatian branch of the League of Communists of Yugoslavia (SKJ). It came into power in 1945. Until 1952, it was known as Communist Party of Croatia (Komunistička partija Hrvatske, KPH). The party dissolved in 1990.

The party was formally founded in 1937 with Pavle Gregorić as its first general secretary. The reasons for KPJ to have its specifically Croatian branch were partly ideological, partly practical. Croatia, just as Slovenia, which would have its Communist Party at the same time, was the most industrialised part of the country, with the biggest percentage of working class in the population, and, therefore, more likely to adopt communism than rural Serbia.

The other, more practical, reason was in the increased marginalisation of Communists in Croatian political life due to public more preoccupied with ethnic issues and position of Croatia within Yugoslavia (cf. Croatia in the first Yugoslavia). Territorial aspirations of Fascist Italy towards Croatian parts of Yugoslavia also presented opportunity for the creation of broad Communist-dominated alliances modelled on Popular Front.

Prior to the formation of the Communist Party of Croatia there was a Croatian-Slavonian Provincial Committee of the Socialist Workers Party of Yugoslavia (Communists) and there was a developed party structure of the Socialist Party of Croatia and Slavonia. Dalmatia had its own structures up to 1937.

KPH, just like KPJ, was illegal and, therefore, remained marginalised, especially after the 1939 Cvetković–Maček Agreement and the creation of the banovina of Croatia within the Kingdom of Yugoslavia.

Party's fortunes dramatically changed with the 1941 Axis invasion of Yugoslavia and creation of the Independent State of Croatia. At the beginning of the Axis occupation of Yugoslavia, Aleksandar Ranković was secretary of the Central Committee of the Communist Party of Croatia. Although KPH had many of its leading figures arrested and killed by new regime, it remained strong enough to form what would become the only truly effective resistance movement in Croatia – the Partisans. KPH was based on ideological rather than ethnic grounds and, therefore, had support in both ethnic Croat and ethnic Serb areas. This allowed Josip Broz Tito's Partisans to mount ultimately successful guerrilla campaign. KPH platform of post-war reorganisation of Yugoslavia on federal grounds also attracted many non-Communist Croatians to its cause, especially in the later stages of war.

In 1945 Yugoslavia was indeed federalised with Croatia becoming a republic, but its nominal autonomy was of little importance with KPJ being heavily centralised and KPH – renamed into SKH in 1952 – being its integral part.

Things began to change in late 1960s with Tito allowing for reformist policies embodied of new generation of Communist leaders. This generation included SKH leaders Savka Dabčević-Kučar and Miko Tripalo who would start movement called the Croatian Spring, advocating for more autonomy of Croatia within Yugoslavia. They advocated against centralism which disproportionately benefited the eastern parts of Yugoslavia, especially Serbia and SR Macedonia.