Assyrtiko or Asyrtiko is a white Greek winegrapeindigenous to the island of Santorini. Assyrtiko is widely planted in the arid volcanic-ash-rich soil of Santorini and other Aegean islands, such as Paros. It is also found on other scattered regions of Greece also found in Australia, Cyprus, Italy, Bulgaria, Turkey, California and Sud Africa.

On Santorini, many old vine plantations (over 70 years of age) of Assyrtiko exist, of which many are non-grafted. These plantations have shown resistance to Phylloxera. As the only European grape vine known to be resistant to wine blight, there is speculation that the actual source of this resistance may arise from the volcanic ash in which the vines grow, and not from the vine itself.