Ishbak (Hebrew: ish'băk; "he will leave; leaving"), also spelled Jisbak and Josabak. According to the Bible he was the fifth son of Abraham, the patriarch of the Israelites, and Keturah whom he wed after the death of Sarah. Ishbak had five brothers, Zimran, Jokshan, Medan, Midian and Shuah.
Josephus tells us that "Abraham contrived to settle them in colonies; and they took possession of Troglodytis and the country of Arabia the Happy, as far as it reaches to the Red Sea." Abraham in all probability, tried to keep them apart from Isaac to avoid conflict while fulfilling God's commission to spread out and inhabit the globe. Little else is known about him, but his descendants may be the people identified in a cuneiform inscription to a people known as Jasbuqu.