Sacnoth (later known as Nautilus) was a small Japanese based video games developer. Sacnoth’s high profile games include Koudelka for the PlayStation, the three Shadow Hearts games for the PlayStation 2, and Faselei! for the Neo Geo Pocket Color.

The name was taken from the name of a supposed magical weapon in a short story by Lord Dunsany, "The Fortress Unvanquishable, Save for Sacnoth," published in 1908 in the collection The Sword of Welleran and Other Stories.