Holy Orders, in the Catholic Church, is the sacrament through which men are ordained as deacons, priests and bishops. It maintains the continuity of the apostles whereby each ordained person is ordained by a successor of an original apostle of Jesus Christ.

There are three degrees to this sacrament. The fullness of Holy Orders is expressed in Episcopal ordination (being ordained a bishop) which is equivalent to being an apostle almost (i.e. apostolic succession). Then there is the ordination of priests who are the co-workers of the bishops and the lowest order is of deacons. They are called simply to serve, but are still given that indelible special character.