İshak Bey of Saruhan

İshak Bey, honorifically Muzafferüddin İshak, was the third ruler of the Saruhanid beylik at Manisa. The son of Fahrüddin İlyas Bey, he succeeded his father after 1362 and reigned until his death in 1388.

In 1366 he ordered the building of Manisa's Great Mosque, with a madrasa added beside it in 1378. On his death his son Hızır Şah took the throne, while his other son Orhan took refuge with the Ottomans.