Royal Diamond (foaled 9 February 2006) is an Irish-bred Thoroughbred racehorse. A slow maturing stayer who was gelded before he appeared on a racecourse, he passed through the hands of five different trainers in a track career which lasted from September 2008 until November 2014. He won several minor races as a three-year-old in 2009 but then lost his form and failed to win in the next two seasons, including and unsuccessful stint as a National Hunt horse. He finally emerged as a top-class performer at the age of six when he rebounded from an unlucky defeat in the Ebor Handicap to record an upset victory in the Irish St. Leger. He was at least as good in the following season when he won the Challenge Stakes, and British Champions Long Distance Cup. He was retired from racing after failing