The Zaporozhian Cossacks, Zaporozhian Cossack Army, Zaporozhian Host, or simply Zaporozhians were Cossacks who lived beyond the Dnieper Rapids. Along with Registered Cossacks and Sloboda Cossacks, Zaporozhian Cossacks played an important role in the history of Ukraine and the ethnogenesis of Ukrainians.

The Cossacks are a predominantly East Slavic Orthodox Christian people originating in the Pontic–Caspian steppe of eastern Ukraine and southern Russia. Historically, they were a semi-nomadic and semi-militarized people, who, while under the nominal suzerainty of various Eastern European states at the time, were allowed a great degree of self-governance in exchange for military service. Although numerous linguistic and religious groups came together to form the Cossacks, most of them coalesced and became East Slavic-speaking Orthodox Christians.