The Karluks (also Qarluqs, Qarluks, Karluqs, Old Turkic: , Qarluq, Persian: خَلُّخ (Khallokh), Arabic قارلوق "Qarluq") were a prominent nomadic Turkic tribal confederacy residing in the regions of Kara-Irtysh (Black Irtysh) and the Tarbagatai Mountains west of the Altay Mountains in Central Asia. They were also known as the Gelolu (, customary phonetic: Gelu, Khololo, Khorlo or Harluut). They were closely related to the Uyghurs. Karluks gave their name to the distinct Karluk group of the Turkic languages, which also includes the Uyghur, Uzbek, and Ili Turki languages.