Tarhuntassa is an undiscovered Bronze Age city south of Hattusa in modern day Turkey. Speculations of its site include Konya, Rough Cilicia, the Göksu valley, and the vicinity of Kayseri. The site of Kilise Tepe (near Mut, formerly known as Maltepe) has also been proposed for it. Another proposed location is Kızıldağ, north of Karaman.
Still others speculate that Tarhuntassa may be a Kaskan name for the city the Greeks called Troy. Its name means "City of Tarhunt (the Luwian storm god)" in the Luwian language, and likely had a Luwian-speaking majority when it was named.
In the early 13th century BC, Muwatalli II moved the Hittite capital from Hattusa to Tarhuntassa, officially as the result of an omen. His son Mursili III later moved the capital back to Hattusa. After Hattusili III deposed Mursili, the new king appointed Muwatalli's son Kurunta as king in Tarhuntassa. The treaty which survives mostly refers to the appointed king as "Ulmi-Tessup", and so some scholars believe that Ulmi-Tessup and Kurunta are two different rulers of Tarhuntassa.
Tudhaliya IV re-ratified Kurunta as king in a treaty inscribed in bronze. At this time, Kurunta was leading his forces to war with Parha. This treaty, unlike previous treaties involving Tarhuntassa, calls to witness the Hittites' vassal kings of Mira and the Seha River Land on the Aegean coast. This implies that Tarhuntassa's stature was now a matter of importance for all western Anatolia.
Kurunta later claimed the title of Great King for himself. Whether or not this claim extended to the whole domain of Hatti, the court in Hattusa contested it (and buried the treaty).