The Oak Island mystery is stories and legends about buried treasure and unexplained objects found on or near Oak Island in Nova Scotia, Canada. The site consists of digs by numerous individuals and groups of people. The original shaft, the location of which is unknown today, was dug by early explorers, and is known as "the money pit".

Since the 18th century, attempts have been made to find treasure and artifacts. Hypotheses about the treasure range from pirate gold to Shakespearean manuscripts to the Holy Grail and the Ark of the Covenant, with the Grail and the Ark having been buried there by the Knights Templar. Various items have been found on the island over the years, some even dating to hundreds of years old. Although these items can be considered treasure in their own right, the alleged treasure has never been found.

A curse on the treasure is said to have originated more than a century ago and states that seven men will die in the search for the treasure before it is found.