The Haileybury Society is the former pupil association for Haileybury and Imperial Service College. Membership of the Society is open to former pupils, past and present members of staff, and Life Governors of Haileybury College, the United Services College, the Imperial Service College, as well as Haileybury and Imperial Service College. It has some 8,500 members in the UK and overseas.
It is a Registered Charity whose aim is to promote educational objectives in connection with Haileybury so as to form a bond of union between the School and the Society and to develop and strengthen the spirit of service to the community.
The Society also promotes reunions, dinners and luncheons both at Haileybury and throughout the UK and overseas. It has several affiliated clubs for members, of which those for rugby, cricket, soccer, golf and shooting are the most active.