Yusuf ibn Umar ibn Shu'ayb (Arabic: يوسف بن عمر بن شعيب‎) was the fifth Emir of Crete, reigning from c. 910–915. The surviving records on the internal history and rulers of the Emirate of Crete are very fragmentary. He is tentatively identified as a son of the third emir, Abu Abdallah Umar (II), and the grandson of the conqueror of Crete and founder of the emirate, Abu Hafs Umar. He is believed to have reigned from c. 910 to c. 915, succeeding his uncle, Muhammad. He was succeeded by his son, Ali.