The Cyclades (/ˈsɪklədiːz/; Greek: Κυκλάδες, romanized: Kykládes, IPA: [ciˈkla.ðes]) are an island group in the Aegean Sea, southeast of mainland Greece and a former administrative prefecture of Greece. They are one of the island groups which constitute the Aegean archipelago. The name (Κυκλάδες νήσοι, Kykládes nísoi, 'encircling islands') refers to the archipelago forming a circle around the sacred island of Delos. The largest island of the Cyclades is Naxos, however the most populated is Syros.

The significant Late Neolithic and Early Bronze Age Cycladic culture is best known for its schematic, flat sculptures carved out of the islands' pure white marble centuries before the great Middle Bronze Age Minoan civilization arose in Crete to the south. (These figures have been looted from burials to satisfy a thriving Cycladic antiquities market since the early 20th century.)

A distinctive Neolithic culture amalgamating Anatolian and mainland Greek elements arose in the western Aegean before 4000 BCE, based on emmer and wild-type barley, sheep and goats, pigs, and tuna that were apparently speared from small boats (Rutter). Excavated sites include Chalandriani, Phylakopi, Skarkos, Saliagos and Kephala (on Kea) with signs of copperworking, Each of the small Cycladic islands could support no more than a few thousand people, though Late Cycladic boat models show that fifty oarsmen could be assembled from the scattered communities (Rutter), and when the highly organized palace-culture of Crete arose, the islands faded into insignificance, with the exception of Delos, which retained its archaic reputation as a sanctuary throughout antiquity and until the emergence of Christianity.

• Ermoupoli, capital of the Cyclades. Syros
• Santorini
• Mykonos
• Naxos
• Folegandros
• Milos
• Irakleia
• Rineia
• Koufonisi
• Traditional vraka (breeches) in the dress of the Aegean islands

The Cyclades includes about 220 islands, the major ones being Amorgos, Anafi, Andros, Antiparos, Delos, Ios, Kea, Kimolos, Kythnos, Milos, Mykonos, Naxos, Paros, Folegandros, Serifos, Sifnos, Sikinos, Syros, Tinos, and Thira or Santoríni. There are also many minor islands (the Lesser Cyclades) including Donousa, Eschati, Gyaros, Irakleia, Koufonisia, Makronisos, Rineia, and Schoinousa. The name "Cyclades" refers to the islands forming a circle ("circular islands") around the sacred island of Delos. Most of the smaller islands are uninhabited.

Ermoupoli on Syros is the chief town and administrative center of the former prefecture.

The islands are peaks of a submerged mountainous terrain, with the exception of two volcanic islands, Milos and Santorini. The climate is generally dry and mild, but with the exception of Naxos, the soil is not very fertile; agricultural produce includes wine, fruit, wheat, olive oil, and tobacco. Lower temperatures are registered in higher elevations and these areas do not usually see wintry weather.

The Cyclades are bounded to the south by the Sea of Crete.^[2]

The Cyclades Prefecture (Greek: Νομός Κυκλάδων) was one of the prefectures of Greece. As a part of the 2011 Kallikratis government reform, the prefecture was abolished, and its territory was divided into nine regional units of the South Aegean region:

Local specialities of the Cyclades include: