Akshak (Sumerian: 𒌔𒆠, akšak) was a city of ancient Sumer, situated on the northern boundary of Akkad, sometimes identified with Babylonian Upi (Greek Opis). Its exact location is uncertain. Classical writers located it where the Tigris and Euphrates rivers are closest together and it was mentioned along with Kish in early records. Archaeologists in the 1900s placed Akshak at the site of Tel Omar (or Tel Umar) where a pair of sites straddles the Tigris, but that turned out to be Seleucia (possibly earlier Upi/Opis) when it was excavated by LeRoy Waterman of the American Schools of Oriental Research, though a fragment with the name Akshak was found there. Michael C. Astour placed it on the Tigris, on what is now the southern outskirts of Baghdad.
Akshak first appears in records of ca. 2500 BC. In the Sumerian text Dumuzid's dream, Dumuzid king of Uruk is said to have been toppled from his opulence by a hungry mob composed of men from the major cities of Sumer, including Akshak. Another king of Uruk, Enshakushanna, is recorded as having plundered Akshak. Following this, Akshak was at war with Lagash, and was captured by Eannatum, who claims in one inscription to have smitten its king, Zuzu. The Sumerian king list mentions Unzi, Undalulu, Urur, Puzur-Nirah, Ishu-Il and Shu-Sin as kings of Akshak. Puzur-Nirah is also mentioned in the Weidner Chronicle as reigning in Akshak when a female tavern-keeper, Kug-bau of Kish, was appointed overlordship over Sumer. Akshak was also mentioned in tablets found at Ebla. In ca. 2350 BC, Akshak fell into the hands of Lugalzagesi of Umma. The Akkadian king Shar-Kali-Sharri reports defeating the Elamites in a battle at Akshak.
- George A. Barton, Dr. Waterman's Excavation at Tel Omar (Ctesiphon), Bulletin of the American Schools of Oriental Research, no. 30, pp. 6-8, (Apr., 1928)
- Howard C. Hollis, Material from Seleucia, The Bulletin of the Cleveland Museum of Art, vol. 20, No. 8, pp. 129-131, 1933
- Professor Waterman's Work at Seleucia, Bulletin of the American Schools of Oriental Research, no. 35, pp. 25-27, 1929
- Gordon, Cyrus Herzl (1992). Eblaitica: essays on the Ebla archives and Eblaite language 3. 3. Winona Lake, Ind.: Eisenbrauns. p. 58. ISBN 978-0-931464-77-5. OCLC 642922991.
- "Dumuzid's Dream". Electronic Text Corpus of Sumerian Literature. Retrieved 2021-07-23.
- Hamblin, William James (2007). Warfare in the ancient Near East to c. 1600 BC. London: Routledge. ISBN 978-0-415-25588-2. OCLC 255477145.
- L Waterman, Preliminary report upon the excavation at Tel Umar, Iraq: conducted by the University of Michigan and the Toledo museum of art, University of Michigan press, 1931