Si'um, also Siium, or Sium (𒋛𒅇𒌝, si-u-um, fl. late 3rd millennium BCE) was the 18th Gutian ruler of the Gutian Dynasty of Sumer mentioned on the "Sumerian King List" (SKL). According to the SKL: Si'um was the successor of Yarlaganda. Sium was the last king of the Gutians before Tirigan (likewise according to the SKL).[1]