Ernest Castle Sykes (31 May 1869 – 30 November 1925) was an English first-class cricketer.
Sykes was a right-handed batsman who played primarily as a wicketkeeper.
Sykes represented Hampshire in one first-class match in 1896 against the touring Australians.
Dean was 0* at the close of Hampshire's first innings and their second innings scored Sykes scored 5*, leaving him with no batting average due to his not out scores.
Sykes died in Bolsover, Derbyshire on 30 November 1925.