All former pupils of King's College School are entitled to join the Old King's Club, and normally join as Life Members. The Life Membership fee is £150. This is normally paid in advance in nine equal instalments of £16.67 added to the tuition fees for each of the pupil's first nine terms, and the pupil becomes a Life Member on leaving the School.

Former pupils who for any reason have not become members, and wish to join, may become Life Members on payment of a fee set on a sliding scale depending on how long ago they left the School. Details will be supplied on application to the Hon. Secretary.

The Club also has Honorary Members. These members are persons who, in the opinion of the Committee, are rendering conspicuous service to King's College School or to the Club. They are elected as honorary members at the Club's Annual General Meeting.

All members are entitled to receive the Club's Newsletter, published twice a year, for ten years without further charge, after which they may subscribe at the current rate. Members may wear the Club's colours, and take part in any of the Club's activities which they wish (though some of the OK sports clubs may require additional subscriptions from participants).