Iddi(n)-Sin (Akkadian: 𒀭𒄿𒋾𒀭𒂗𒍪: Iddî-Sîn) was a King (𒈗 Šàr, pronounced Shar)[2] of the Kingdom of Simurrum around 2000 to 1900 BCE.

Simurrum was an important city state of the Mesopotamian area, during the period of the Akkadian Empire down to Ur III.

[6] In inscriptions, the name of Iddi(n)-Sin is written 𒀭𒄿𒋾𒀭𒂗𒍪, with one silent determinative (𒀭, DINGIR) before the remaining part of the name, 𒄿𒋾𒀭𒂗𒍪.

[6] Iddi-Sin is also known from a stele, which he inscribed in the Akkadian language, now in the Sulaymaniyah Museum, Iraq.

A seal showing Iddi(n)-Sin and his son Zabazuna (Akkadian: 𒍝𒁀𒍪𒈾: Za-ba-zu-na), is also known from the Rosen collection.