For other places named Ithaca, see Ithaca (disambiguation).

Ithaca, or Ithaka (Ithaki in modern Greek) is an island in the Ionian Sea, in Greece with an area of 96 km² and 5,000 inhabitants. It is the legendary home of Odysseus from Homer's Odyssey, and, according to some scholars, the home of Homer himself. It is an independent municipality of the prefecture of Kefallinia.

The island has been inhabited since the 2nd millennium BC. It was the capital of Cephalonia during the Mycenaen period. Through the Trojan War it was ruled by the legendary king Odysseus. The Romans occupied the island in the 2nd century BC, and later it became part of the Byzantine empire. The Normans ruled Ithaca in the 12th and 13th century, and after a short Turkish rule it fell into Venetian hands. Ithaca was then occupied by France at the end of the 18th century and in 1809 it was conquered by the British. In 1864 Greeks liberated it.

Much of the island's architecture was destroyed in an earthquake in 1953.

The capital, Vathy , has one of the world's largest natural harbours.

As of 2002, Ithaca became a popular destination for holiday tourists on day visits from the other Ionian Islands, especially after Charles, Prince of Wales and the late Diana, Princess of Wales spent part of their honeymoon there.