The Dodecanese (Greek Dodekanisa, Turkish Onikiada, both meaning "twelve islands"; Italian Dodecaneso) are a group of 12 larger plus 150 smaller Greek islands in the Aegean Sea, off the southwest coast of Turkey. They have a rich history, and many of even the smallest inhabited islands boast dozens of Byzantine churches and medieval castles.

The current Greek administrative region of the Dodecanese (a subdivision of the South Aegean periphery) consists of 163 total islands of which 26 are inhabited. Twelve of these are major, giving the chain its name. The most historically important and well-known is Rhodes (Rodos), which for millennia has been the island from which the region is controlled. Of the others, Kos and Patmos are historically more important; the remaining nine are Astipalea, Kalimnos, Karpathos, Kasos, Leros, Nisyros, Simi, Tilos and Kastelorizo (which actually lies in the eastern Mediterranean sea). Other notable islands in the chain incysos) are significant. The economy of the whole island is geared toward tourism; the island's primary source of income.