Cluedo (), known as Clue in North America and South Korea, is a murder mystery game for three to six players (depending on editions) that was devised in 1943 by British board game designer Anthony E. Pratt. The game was first manufactured by Waddingtons in the United Kingdom in 1949. Since then, it has been relaunched and updated several times, and it is currently owned and published by the American game and toy company Hasbro.

The object of the game is to determine who murdered the game's victim, where the crime took place, and which weapon was used. Each player assumes the role of one of the six suspects and attempts to deduce the correct answer by strategically moving around a game board representing the rooms of a mansion and collecting clues about the circumstances of the murder from the other players.

Numerous games, books, a film, television series, and a musical have been released as part of the Cluedo franchise. Several spinoffs have been released featuring various extra characters, weapons and rooms, or different game play. The original game is marketed as the "Classic Detective Game", and the various spinoffs are all distinguished by different slogans.

In 2008, Cluedo: Discover the Secrets was created (with changes to board, gameplay and characters) as a modern spin-off, but was criticised in the media and by fans of the original game. Cluedo: The Classic Mystery Game was then introduced in 2012, returning to Pratt's classic formula but also adding several variations.