Saʽd ibn ʽUbadah ibn Dulaym (Arabic: سعد بن عبادة بن دليم) (d. 637) was the chief of the Sa'ida clan of the Khazraj tribe in Medina in the early seventh century. He was later recognised as the chief of the whole Khazraj tribe, and then of all the Ansar. He was a prominent companion of the Islamic prophet Muhammad and he made an abortive attempt to nominate himself as caliph of Islam after Muhammad's death.