Keros is an uninhabited and unpopulated Greek island in the Cyclades about 10 km (6 mi) southeast of Naxos. Administratively it is part of the community of Koufonisia. It has an area of 15 km2 (6 sq mi) and its highest point is 432 m (1,417 ft). It was an important site to the Cycladic civilization that flourished around 2500 BC. It is now forbidden to land in Keros.

Cycladic culture was a Bronze Age culture found throughout the islands of the Cyclades in the Aegean Sea. In chronological terms, it is a relative dating system for artifacts which serves as a roughly contemporary dating system to Helladic chronology and Minoan chronology (Crete) during the same period of time.