Larry is a British domestic tabby cat who has served as Chief Mouser to the Cabinet Office at 10 Downing Street since 2011. He is cared for by Downing Street staff and is not the personal property of the prime minister of the United Kingdom.

Chief Mouser to the Cabinet Office is the title of the official resident cat at 10 Downing Street, the residence and executive office of the Prime Minister of the United Kingdom in London. There has been a resident cat in the British government employed as a mouser and pet since the 16th century, although modern records date only to the 1920s. Despite other cats having served Downing Street, the first one to be given the official title of chief mouser by the British government was Larry in 2011. Other cats have been given this title affectionately, usually by the British press. In 2004 a study found that voters' perceptions of the chief mouser were not completely above partisanship.