The Red Cross of Constantine is officially The Masonic and Military Order of the Red Cross of Constantine and the Orders of the Holy Sepulchre and St. John the Evangelist, the latter two of which are called the Appendant Orders. There are also two chair degrees conferred on the Viceroy and Sovereign of a Conclave, and two honorary orders: Knight Commander of Constantine and Knight Grand Cross. The governing body of the Order for the United States of America, the Republic of Mexico and the Republic of the Philippines and their territories is styled The United Grand Imperial Council of Knights of the Red Cross of Constantine and Appendant Orders for the United States of America, Mexico and the Philippines.

The purpose of the Constantinian Orders are to commemorate the first elevation of Christianity from the position of a despised and proscribed heresy to that of a legally recognized and honored religion, to cultivate the social virtues, appeal to the intellectual and moral qualities, preserve as far as possible the customs of the fraternity and bring about good fellowship and understanding between all branches of Masonry.

Knights Companions of the Order meet in Conclaves of the Red Cross of Constantine and a member must be a Royal Arch Mason in good standing and subscribe to a belief in the Christian religion as revealed in the New Testament. Membership is by invitation and each Conclave has a prescribed membership limit.