The Mount School York will start taking boys in early years again from September this year and then, over the course of the next eight years, will become co-educational for primary school age children.
The school currently has 210 pupils and claims Dame Judy Dench as one of its former students.
Principal David Griffiths said the move 'makes sense' and is a return to form for a school that taught younger boys from 1901-1936 and then again from 1991-2018.
The secondary school will remain for girls only with Mr Griffiths saying it will never, ever go co-ed.
"For us it's a return to what we always were. We're a small family school and this just fits," he said.
"We have informed parents and the decision has been well-received, but, as with any change, there's always going to be some people, who didn't see it coming."
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