The Anatolian beylik of Menteş (1260–1424), with its capital in Milas in southwest Anatolia and headquartered in Beçin castle near that city, is one of the frontier principalities established by Oghuz Turkish clans after the decline of the Seljuk Sultanate of Rum.

The Beylik is named after its founder, Menteş Bey.

It comes into existence by the year 1290.

The beylik's core territory corresponds roughly to ancient Caria or the later Muğla Province in Turkey, including the province's three protruding peninsulas.