Kos or Cos (Greek: Κως) is a Greek island in the south Sporades group of the Dodecanese, next to the Gulf of Gökova/Cos. It measures 40 kilometres (25 mi) by 8 kilometres (5.0 mi), and is 4 kilometres (2.5 mi) from the coast of Bodrum, Turkey and the ancient region of Caria. Administratively the island forms a separate municipality within the Kos peripheral unit, which is part of the South Aegean Periphery. The principal town of the island and seat of the municipality is Kos town. The island has a population of 30,947.
A person from Kos is called a "Koan." The word is also a possessive, as in "Koan goods."