Cluedo (Clue in North America) is a crime fiction board game originally published by Waddingtons at their peak in the United Kingdom in 1948. It was devised by Anthony E. Pratt, a solicitor's clerk and part time clown from Birmingham, England. It is now published by the United States game and toy company Hasbro, which acquired its U.S. publisher Parker Brothers as well as Waddingtons.

The game is set in a mansion, with the board divided into different rooms. The players each represent a character who is a guest staying at this house, whose owner, Dr. Black (Mr. Boddy in the North American version), has been found murdered. Players attempt to solve the murder. The solution to the murder requires the three components of Suspect, Weapon, and Room.

More games, books and a film have been released as part of the Cluedo franchise.

Spin-off games

Waddingtons, Parker Brothers and Hasbro have created many spin-off versions of the game. Spin-off games fall under two categories, alternative rule variations such as Clue Master Detective, and themed versions such as Simpsons Clue. These include:

• Clue VCR Mystery Game (1985) released as Cluedo: The Great Video Detective Game in the UK. It uses an hour-long VHS tape containing humorous scenes of the suspects interacting at Boddy Mansion shortly after Mr. Boddy's death instead of a board. Players uncover details of several murders per game by matching clues given on cards to the action on the video. Only five weapons (Candlestick, Knife, Gun, Rope, and Poison) and five rooms (Dining Room, Kitchen, Hall, Conservatory, and Library) are featured but there are a total of ten suspects (original six plus M. Brunette, Madam Rose, Sgt. Gray, and Miss Peach).
• Super Cluedo Challenge (1986) is an advanced version of the Cluedo rules, introducing three new characters (Captain Brown, Miss Peach and Mr. Slate-Grey) and three more weapons (the blunderbuss, poison and axe). The rules are greatly expanded, with each card having coloured and numbered squares in each corner, which are uncovered by special card holders. These allowed 'clues' to be given by uncovering a small segment of the card, showing only a colour/number. Rather than the remaining cards being dealt out at the start of the game, they had to be 'discovered' by reaching one of the many blue counters scattered on the board.
• Clue VCR II: Murder in Disguise (1987) more scenarios to add to the first VCR game.
• Clue Master Detective (1988) released as Super Cluedo in France) is an expanded version of the original game. In addition to the original characters, weapons and rooms, the game introduces four new characters (Mme. Rose, Sgt. Grey, M. Brunette and Miss Peach), two weapons (poison and horseshoe), and seven rooms (courtyard, gazebo, drawing room, carriage house, trophy room, studio and fountain) to the mansion. This version was also made into a computer game.
• Clue: The Great Museum Caper (1991) is rather different from the original. One player is a thief moving in a museum stealing paintings, while the other players cooperate to catch the thief. The thief keeps track of his position secretly on paper and is thus not seen by the detectives, until the thief is spotted by a detective or the museum's security system. Ideally, multiple rounds are played, with each player getting to be the thief once. The winner of the match is then the thief who stole the most paintings without getting caught.
• Cluedo Card Game (1992) is a shedding-type card game, where players attempt to match cards featuring the locations, weapons, and characters from the original game with a central pile of cards.
• Clue Little Detective (1992).
• Cluedo Junior (1993)  is the first Junior game for Cluedo. Instead of finding the murder, the players need to find the ghost of their ancestors and remember where they are.
• Cluedo Super Sleuth (1995) is another advanced version of the Cluedo rules, though in a different manner. There is no set board to this game, instead the board is made up of twelve tiles which are laid out randomly as players enter new rooms, to create a 4x3 grid. The murder cards remain unchanged to the basic edition, but are not dealt to each player, instead there are 'clue' squares on the board marked by small plastic magnifying glasses, which players collect to get clues. In addition to the "clue" counters there are also item counters, which allow the player to pick a card from an item deck. These item cards allow such things as making more than one suggestion per turn, or moving an incidental character. There are three incidental characters in the game (Inspector Grey, Hogarth the Butler, and the Black Dog) who can serve as help or hindrance, and are controlled through the item and event cards. Event cards are drawn from a deck upon a certain roll of the die and can have varying impact on a game.
• Clue Jr.: The Case of the Hidden Toys (1998) is themed for children. Instead of solving a murder, the children search for clues for the whereabouts of some lost toys. The rules are significantly different from those for the regular board game. The characters, which look like the original game's suspects as children, are named Mortimer Mustard, Georgie Green, Peter Plum, Wendy White, Polly Peacock, and Samantha Scarlet.
• Cluedo: 50th Anniversary (1999), also released as Clue: 50th Anniversary this edition came in a deluxe format with an extra murder weapon, a bottle of poison.
• Cluedo Passport to Murder (2000) was an update of Super Cluedo Challenge with the setting changed to an Orient Express style train in Istanbul station. There is very little change to the mechanics of the game (except you can only play the six original characters), with mainly cosmetic changes and updates to the characters.
• Cluedo Card Game (2002) is a different card game from the previous game, this time the user has to deduct the Dr. Black's killer, their escape vehicle and their destination.
• Clue FX (2003) released as Cluedo SFX in the UK, (2004), and Super Cluedo Interactif in France, (2004) is another departure from the original rules. You play as one of four new characters (Lord Grey, Lady Lavender, Miss Peach and Prince Azure, adding a non-caucasian character since the early Asian Miss Scarlet, none of whom are suspected in the crime. The murder is not of Dr. Black (Mr. Boddy) but of his attorney Miles Meadow-Brook. The usual suspects are in place, this time bolstered by two new people Mrs. Meadow-Brook and Rusty the Gardener. The gameplay is completely different though, with the introduction of the electronic section announcing moves and clues and no die rolling. Instead players move from location to location to track down each of the suspects to gain their clues, before finding Inspector Brown to make an accusation.
• Cluedo Junior: The Case of the Missing Cake (2003) is another children's variation where you have to find out who ate the cake.
• Clue Mysteries (2005), released in the UK as Cluedo Mysteries(2006) This is another change of rules, and this time the gameplay is based heavily on another boardgame called "Mysteries of Old Peking".
• Cluedo DVD Game (2005) This is the most recent edition of the game, with different rules based around DVD interaction. Instead of a murder, Dr. Black has had an item stolen and, in addition to guessing the criminal, location (room) and stolen object, the time of day when the crime took place also has to be discovered. In each turn players guess three of these four unknowns; and from time to time Inspector Brown and the butler, Ashe, show up via the DVD with helpful information.