Canberra Grammar School – an elite boys-only ACT institution – could soon welcome the other half of society.

Canberra Grammar School has announced it will transition to co-education from next year.

It came after the school’s board decided unanimously to welcome females, combined with social and educational changes.

Canberra Grammar is currently co-educational from pre-school to Year 2 but from Year 3 onwards there are no girls allowed.

Under the changes being phased-in from next year, girls will be able to apply for places in Year 3 and 4.

In its second transitionary phase, girls will get to apply for Years 7 and 11 in 2017.

Canberra Grammar School headmaster Justin Garrick says the school has realised it must face the realities of the world into which it sends its students – a world with more than one gender.

“We looked at the nature of the world and the nature of the educational offering we're giving,” he said.

“The boys that we have with us now are going to be working with bright, aspirational, talented, educated young women, and they're going to be shaping together virtually every field and industry that there is.

“We felt that they needed to learn to think together, to learn together, to work together.”

The changes will also extend to the Canberra Grammar boarding house.

“Our commitment to this is full ... there are of course, though, practical difficulties,” Mr Garrick said.

“We undoubtedly will need to make some physical changes to the school.

“We'll be looking at our options and plans for boarding, and we'll start taking expressions for boarding for 2018.”

But there are no such plans over at Canberra Girls Grammar School.

Principal Anne Coutts says her school will not become co-educational or merge with Canberra Grammar.

“We genuinely believe that these girls are leaders and that they can do that in the workplace, but they need the encouragement, the support and the good education to do that,” she told the ABC.

“Our expertise is in girls' education. We believe that girls don't just need equal opportunity, but every opportunity, and we give them every opportunity in a girls' school.”

Ms Coutts says school is not the workplace.

“It equips and prepares people for the workplace, and therefore I believe that girls need an environment and a challenge and encouragement that equips them for their future,” she said.