Kayumarth I (also spelled Gayumarth I or Kayumars I; Persian: ملک کیومرث یکم‎) was the ruler (ustandar) of the Baduspanids from 1394 to 1453, with a three-year interruption. An active expansionist ruler, his kingdom experienced a resurgence during his long reign, which included the reconquest of Rustamdar. He was often at odds with his suzerain, the Timurid ruler Shah Rukh (r. 1405–1447). After his death, a dynastic struggle followed, which resulted in his kingdom being split up by his sons Iskandar IV and Ka'us II, in Kojur and Nur respectively.