Sultan of Rûm |
|Predecessor||Kilij Arslan II|
|Predecessor||Kilij Arslan III|
Kuyucak, Sultanate of Rum
|Consort||Dawlat Raziya Khatun, daughter of Manuel Maurozomes|
Muzaffar al-Din Numan
|Father||Kilij Arslan II|
Kaykhusraw I ( Old Anatolian Turkish: كَیخُسرو or Ghiyāth ad-Dīn Kaykhusraw ibn Kilij Arslān; Persian: غياث الدين كيخسرو بن قلج ارسلان), the eleventh and youngest son of Kilij Arslan II, was Seljuk Sultan of Rûm. He succeeded his father in 1192, but had to fight his brothers for control of the Sultanate, losing to his brother Suleiman II in 1196.  He ruled it 1192–1196 and 1205–1211.
Kaykhusraw's date of birth is unknown. He was the eleventh and youngest son of Kilij Arslan II ( r. 1156–1192). His mother was of Byzantine ancestry. Kaykhusraw received a good education during his upbringing, learning other languages besides his native Turkish, which was Persian, Arabic, and Greek. 
In 1192/93, Kaykhusraw returned the Byzantine nobleman, Theodore Mangaphas, to Emperor Isaac II after receiving assurances of Mangaphas treatment.  With his brother, Rukn ad-Din Suleiman Shah, quickly advancing towards Konya, Kaykhusraw fled to Constantinople in 1196.  He lived in Constantinople from 1197–1203, possibly even being baptised.  A mathnawi written by Kaykhusraw himself compares his destiny during that period to that of the legendary Iranian hero Jam ( Jamshid), who had to go into exile after losing his divine fortune ( farr). 
Kaykhusraw seized Antalya in 1207 from its Niceaen garrison which furnished the Seljuk sultanate with a port on the Mediterranean.  It was during this year, Kaykhusraw founded a mosque in Antalya. 
Kaykhusraw was killed at the Battle of Antioch on the Meander in 1211.  His son Kayqubad I, by Manuel Maurozomes' daughter, ruled the Sultanate from 1220 to 1237, and his grandson, Kaykhusraw II, ruled from 1237 to 1246.  Kaykhusraw's body was taken to Konya, where it was buried in the ancestral tomb of his family.