Robert John Hadley (born 22 October 1951) is a former Welsh cricketer. Hadley was a right-handed batsman who bowled left-arm fast-medium. He was born at Neath, Glamorgan.

While studying at St John's College, Cambridge,^[1] Hadley made his first-class debut for Cambridge University against Warwickshire at Fenner's in 1971. He made six further first-class appearances in that season for the university.^[2] In that same season he also made two first-class appearances for Glamorgan, against Leicestershire and Somerset in the County Championship.^[2] Against Leicestershire he took his maiden five wicket haul, with figures of 5/32 during Leicestershire's first-innings.^[3] These were to be his only first-class appearances for Glamorgan. He continued to play first-class cricket for Cambridge University in 1972 and 1973, making seventeen further first-class appearances, the last of which came against Oxford University in The University Match at Lord's.^[2] In total he made 24 first-class appearances for the university, taking 47 wickets at an average of 30.17, with best figures of 5/31.^[4] These figures were one of two five wicket hauls he took for the university and came against Sussex in 1972.^[5] He also made two first-class appearances for a combined Oxford and Cambridge Universities team, against the touring Australians in 1972 and the touring New Zealanders in 1973.^[2]

Hadley also appeared in three List A matches for Cambridge University in the 1972 Benson & Hedges Cup, playing against Warwickshire, Worcestershire, and Northamptonshire in the group stages of the competition.^[6] He had little success in these matches, taking just a single wicket.^[7]

He became a doctor.^[8]