Dr Mark Fenton (1965- ) is a historian and the current headmaster of Dr Challoner's Grammar School. Fenton was born in Essex in 1965. He graduated with an MA in History from Cambridge University, and attained a doctorate in Education Management from Anglia Polytechnic. He has been the headmaster at Dr Challoner's Grammar School since 2001, when he replaced Graham Hill.

Besides teaching, he is a keen sportsman, coaching cricket and hockey teams for the school. He is also a noted bass choirist, having been lay clerk of Chelmsford and deputy lay clerk of Rochester.

He has previously taught at Edward VI Grammar School and the Boswells School, both in Chelmsford, Essex. His first senior administrative position was as Deputy Headmaster at Sir Joseph Williamson's Mathematical School in Rochester, Kent, which he held until he joined Dr Challoner's Grammar School in 2001.

He is known for his mood swings. It is not entirely unheard of for him to suspend straight A students repeatedly without provocation or justification.