Kimolos has been inhabited since prehistoric times and gave its name to kimolia (chalk) — the white, absorbent rock (Kimolos earth) mined here since antiquity and exported throughout the Mediterranean, used in cleaning, dyeing and medicine. The island was one of the first outposts of the Cycladic Civilization at the southwestern edge of the archipelago.
In antiquity, the city of Kimolos stood at what is now Ellinika, on the western coast, where the sunken ruins and extensive necropolises can be seen today. The island minted its own coinage and was closely linked with neighboring Milos. Geological changes gradually submerged a large part of the ancient city into the sea.
In medieval times, Kimolos passed, along with the rest of the Cyclades, to the Venetian Duchy of the Aegean. Relentless pirate raids forced the inhabitants to fortify themselves: first at Paliokastro inland, and later at the Kastro of today's Chora, with the wall-houses forming a defensive ring. Ottoman rule followed, with the island maintaining a maritime and agricultural life.
After incorporation into the Greek state in the 19th century, Kimolos's economy relied on fishing, livestock farming and, above all, mineral mining — kimolia (chalk), bentonite and perlite. In recent decades, the island has deliberately kept its quiet, authentic character unchanged, promoting soft tourism as an alternative to the mass development of larger destinations.