Treasure Island as a whole was more of a production of Robert Louis Stevenson's imagination and inspiration from earlier adventure stories than anything else. Robinson Crusoe by Daniel Defoe, Tales of a Traveller by Washington Irving, and the novels of James Fenimore Cooper all prompted Stevenson's imagination when crafting what would become one of his most iconic works. However, a few details, characters, and incidents from the novel were taken from real life.

The island itself came from a drawing Stevenson and one of his stepsons drew for fun on a rainy day. Israel Hands was named after a pirate mentioned as a member of Blackbeard's crew in the nonfiction book A General History of the Pyrates (a book that was another major inspiration for Stevenson).

Also, the appearance of Long John Silver was based on William Henley. Henley was not a pirate, but one of Stevenson's friends, a boisterous man with one leg. The Oxford Companion to Children's Literature's entry on Treasure Island also claims that the episode with Jim in the apple barrel overhearing the mutineers' plans was based on something similar that happened to Stevenson's father.

One major possible real-life source may have been the murder of Captain George Glas by pirates in 1765. The pirates killed not only the captain, but his wife, ten-year-old daughter, and everyone else on the ship before leaving with the riches on board. They buried the treasure on an island to reclaim later but were caught and hanged in Dublin. Unlike the treasure in Stevenson's book, Glas's treasure was never recovered, even after his murderers were brought to justice.