Kon-Tiki was the name given to a raft by Norwegian explorer and writer Thor Heyerdahl in his 1947 expedition to show there were no technical reasons to prevent people from South America having settled Polynesia in the south Pacific in Pre-Columbian times. "Kon-Tiki" is also the name of the popular book which Heyerdahl wrote about his adventures.

Heyerdahl and a small team went to Peru, where they used trees and other native materials to construct a balsawood raft said to be of native style. They sailed it for 101 days over 4,300 miles across the Pacific Ocean before smashing into the reef at Raroia in the Tuamotu Islands on August 7, 1947. The only modern equipment they had was a radio. For food, they lived off the fruits of the ocean.

While this was an interesting experiment, which demonstrated the seaworthiness of Heyerdahl's raft, most anthropologists continue to believe, based on physical, cultural and genetic evidence, that Polynesia was settled from west to east, migration having begun from the Asian mainland, not South America. The Kon-Tiki adventure is often cited as a classic of pseudoarchaeology.

The book Kon-Tiki was a best-seller, and a documentary motion picture of the expedition won an Academy Award in 1952.