"It's also about Huntley moving with the times, and keeping up with what our families need and want. Our traditions have served us well, but it's time for us to invite girls into Huntley. The change will benefit our school in more ways than just financial ones.
"The key thing in terms of how children learn is the quality of teaching. We place enormous emphasis on quality teaching that takes into account students' individual needs and styles, so that all of them flourish at Huntley. That will continue to be true when we are co-ed."
Mr Gay said for the past five years parents had come to him suggesting the school, with a roll of 135, include girls in its roll.
"There's really no option for boarding girls in the lower North Island, and parents want to offer their girls the same opportunities as their boys. Society is changing and the days of offering boys-only opportunities are long gone.
"It makes sense for us to offer what modern families want."
Renovations to existing facilities and building work would be carried out over the summer holidays in time for the arrival of girls next year, Mr Gay said.
Richard Hogg, chair of the school's board, said a focus group was set up six months ago to investigate the change.
"They studied the business of introducing girls into a boys' school quite extensively, looking at models in the UK and in New Zealand."
Mr Hogg is also involved with the school's Old Boys' Association and he said members he talked to were supportive of the change.
"Some will probably have difficulty with the change but all those I've talked to have been unanimous in their support. All the feedback we've had has been positive and people are very, very excited."
Rangitikei Mayor Chalky Leary said he was surprised to hear of the move.
"I can't really make an informed comment about the change, it's outside my field of expertise ...I'm a sheep farmer and a mayor."
But Marton was very proud of Huntley School, he said. "They will have a very good reason for changing to co-ed, they certainly wouldn't do anything to jeopardise the reputation of the school, I do know that. Huntley has a fine tradition...you know maybe this change to co-ed is a trend now, who knows in this world. It's full of surprises."