Castle of Riddles is a text adventure released by Acornsoft for the BBC Micro (in 1982) and Acorn Electron (1984) home computers.

The player must use a simple 'verb-noun' format (e.g. 'Go North', 'Get lamp') to control the game.

Unlike Killworth's other Acornsoft adventures, Castle of Riddles was not updated and reissued by Topologika so it became unavailable after 1985 when Acorn Computers (parent company of Acornsoft) pulled out of the games publishing market.

The player must navigate the castle, solve problems and avoid booby traps set by the warlock in order to recover the magic ring for the wizard.

Points are awarded for picking up treasure and again for depositing it in the safe and completing certain tasks.