taken from the OA page at Scouting.org:
The Order of the Arrow membership requirements are:
Unit leader approval. To become eligible for election, a Boy Scout or Varsity Scout must be registered with the Boy Scouts of America and have the approval of his unit leader prior to the election. The unit leader must certify his Scout spirit (i.e., his adherence to the Scout Oath and Law and active participation in unit activities). The unit leader must also certify that the nominee meets all specified requirements at the time of this annual election.
Youth membership qualifications. All members of, or candidates for membership in, the Order of the Arrow who are under 21 years of age shall be considered youth members or candidates for youth membership, subject to meeting the following requirements:
- Be a registered member of the Boy Scouts of America.
- Hold the First Class rank of the Boy Scouts of America, as a minimum.
- After registration with a troop or team, have experienced 15 days and nights of Boy Scout camping during the two-year period prior to the election. The 15 days and nights must include one, but no more than one, long-term camp consisting of six consecutive days and five nights of resident camping, approved and under the auspices and standards of the Boy Scouts of America. The balance of the camping must be overnight, weekend, or other short-term camps.
For more information: