Mislav (Latin: Muisclavo) was a duke (Croatian: knez) in Croatia from around 835 until his death around 845.
Mislav came to power at some point after Vladislav as the Duke of Dalmatian Croatia. He ruled from Klis in central Dalmatia, when he made Klis Fortress seat to his throne. Mislav was a pious ruler. He built the Church of Saint George in Putalj (on the slopes of hill Kozjak). Today's Kaštel Sućurac got its name after the village of Sv. Jure (Saint George), named after that church.