Emmanuel Lionel "Manny" Mercer (1928 – 26 September 1959) was a Thoroughbred horse racing jockey who was one of British racing's brightest stars when he died in a racing accident. A brother to jockey Joe Mercer, he was married to the daughter of trainer Harry Wragg. Their daughter, Carolyn, married jockey Pat Eddery.A leading jockey throughout most of the 1950s, in 1954 Manny Mercer won eighty-eight races, finishing second in the jockey standings to Doug Smith.