Brotherhood membership is the second level of membership in the Order of the Arrow. After a minimum of ten months, an Ordeal member may "seal" their membership in the Order by accepting an additional obligation of service to their lodge, council, or scout camp.

By demonstrating exceptional service after a minimum of two years, a Brotherhood member may be recommended to the national committee for elevation to the Vigil Honor. However, the Vigil Honor is not a third level of membership-- they are still a Brotherhood member, but one who has been bestowed with the Vigil Honor.

Originally, the ceremonies for Ordeal members and Brotherhood members where combined into what was called the First Degree, and what is now known as the Vigil Honor was then referred to as the Second Degree. It was later called the Third Degree, after the First Degree became separated into the First Degree and the Second Degree-- these levels of membership developed into the Ordeal Honor and Brotherhood Honor, respectively, and then simply the Ordeal and Brotherhood levels of membership.