The Euphrasian Basilica or the Cathedral Basilica of the Assumption of Mary is a Roman Catholic basilica in the Istrian town of Poreč, Croatia. The episcopal complex, which comprises the basilica itself, a sacristy, a baptistery and the bell tower of the nearby archbishop's palace, is an excellent example of early Byzantine architecture in the Mediterranean region.

Poreč is a town and municipality on the western coast of the Istrian peninsula, in Istria County, west Croatia. Its major landmark is the 6th-century Euphrasian Basilica, which was designated a UNESCO World Heritage Site in 1997.