Iptar-Sin orIB.TAR.Sîn^{[nb 1]} (reading uncertain), was the 51stAssyrian king according to theAssyrian King List.^{[i 1]} He reigned for 12 years some time during the 17th century BC.

TheAssyrian King List provides a sequence of five kings with short reigns purported to be father-son successions, leading Landsberger to suggest thatLibaya,Sharma-Adad I and Iptar-Sin may have been brothers ofBelu-bani rather than his descendants. The list reports Iptar-Sin as the son of Sharma-Adad I. He is omitted from the list on another fragment.^{[i 2][2]} He is called LIK.KUD-Šamaš on theSynchronistic King List^{[i 3]} which gives his Babylonian counterpart as^mDIŠ+U-EN (reading unknown), an unidentified person inserted between the reigns of Gulkišar and his son Pešgaldarameš of theSealand Dynasty.

He was succeeded by Bazaya, son of Belu-bani.

• 17th-century BC Assyrian kings
• 17th-century BC deaths

• Articles with short description
• Short description is different from Wikidata
• Year of birth unknown