"His interest in boys' education is reflected in the dedication he has brought to the role."
Mr Fiet's last day will be at the end of April.
The school board has begun a search for a new headmaster. As an interim measure,
it has appointed an acting headmaster, Mr Willy Kersten, who will start at Hereworth after
Queen's Birthday weekend and act in this capacity for the remainder of the school year.
In the five weeks before Mr Kersten arrives Hereworth School deputy heads Kate Field and Deb Richardson will together fill the role of acting headmaster.
They will be supported
by a specially appointed board subcommittee of Gareth Kilsby and Sarah Park.