'The Adventure of the Reigate Squire' (also called 'The Reigate Puzzle') is a Sherlock Holmes story by Sir Arthur Conan Doyle, first published in The Strand Magazine and Harper's Weekly in June 1893. It's part of The Memoirs of Sherlock Holmes and was ranked 12th in Doyle's favorite Holmes stories.

In this story, after a tough case in France, Holmes and Watson visit Colonel Hayter's estate near Reigate, Surrey, to rest. Nearby, a burglary occurred at the Acton estate, stealing odd items, and then a murder happens at the Cunningham estate—William Kirwan, the coachman, is killed. Inspector Forrester investigates, finding a torn note with the words 'quarter to twelve' in Kirwan's hand. Holmes is immediately intrigued.