The O.T.O. operates along a structure that involves a series of initiations. You do not have to be an initiate in order to attend the Gnostic Mass or most events. There are some activities within the Lodge, however, which are for initiates only.
The O.T.O. initiation is a physical ceremony and in order to undertake it you need to be sponsored by two members of the Order. In addition, you need to be of 19 years of age or older. The introductory degree is called Minerval or 0 degree. A member of the Minerval degree is considered to be a guest of the Order; full membership starts from the First Degree, and continues up to nine major degrees. Membership in O.T.O. is private. Names and addresses of members are kept confidential from the general public and from the bulk of O.T.O. members.
Those who are interested in joining the O.T.O. can make their intention known by contacting the Lodge. From Minerval to the Fourth degree, it is up to the applicant to meet body members, and request their sponsorship. After the Fourth degree, initiation is by invitation.