Khustup (Ustupu) is a mountain in the Zangezur uezd of the former Yelizavetpol (Ganja) governorate, later in the former Gafan district, and currently in the Syunik province. Its height is 3206 m.

The toponym was coined by combining the tribal name “Khus, Guz, Ghuz” which is a phonetic form of the ethnonym “Oghuz”, an ancient Turkic tribe and the word “tup” (tub, tüp) used to mean “the bottom of the mountain, foothills”, “downstream” in Turkic.