The tradition of boarding is central to the ethos and success of Kilgraston. A dedicated team of Housemistresses and Resident staff create the characteristic home atmosphere which is warm and welcoming for all pupils, boarders and day girls. Boarding education encourages the development of inner resources in young people and often promotes friendships which last a lifetime. For Sixth Formers in particular, the opportunity to board provides a taste of life away from home, a little like university - but in a more structured environment.

Boarding at Kilgraston is organised according to age group and all boarders, with the exception of the very youngest, have their own study bedroom. Each boarding area has its own Common Room for socialising and relaxing, and there are kitchen facilities available in each area which can be used with the appropriate degree of supervision for each age group. The girls are routinely encouraged to take a degree of responsibility for how their Common Rooms are decorated to ensure that the facilities on offer are in line with modern expectations.