Circus Ring (8 February 1979–25 November 2009) was a British Thoroughbred racehorse and broodmare. Despite never contesting a Group One race she was the leading two-year-old filly in the United Kingdom in 1981 when she was unbeaten in three races including the Princess Margaret Stakes (by ten lengths) and the Lowther Stakes. She then developed injury problems and finished unplaced in her only appearance in 1982.