Khios is a Greek island in the Aegean Sea. Also known as Chios.

Population is about 52,290 (census of 2001). Area 910 km². The capital is also called Khíos, it is a port and the island's chief town. Other settlements include Volissos, Marmaro and Oinoussa. The island is famous for its scenery and good climate.

The island's chief export is mastic but it also produces olives, figs, and wine.

The Korai Library, one of the most important in Greece, is in Khios, it contains 95,000 volumes.

Khíos was colonized by Ionians but has been occupied by the Persians, part of the Delian League and the Byzantine Empire. Before passing through the possession of the Latin emperors of Constantinople, the Genoese, the Ottoman Turks (there was a massacre of the islanders after a rebellion in 1822) and finally the Greeks after the First Balkan War (1912).

Khíos claims to be the birthplace of Homer, Hippokrates the mathematician, and Oenopides. Oenopion, a legendary king, is said to have brought winemaking to the island.