The term Holy Orders is used by many Christian churches to refer to ordination or to those individuals ordained for a special role or ministry. In the Roman Catholic (Latin: sacri ordines), Eastern Catholic, Eastern Orthodox (ιερωσύνη [hierōsynē], ιεράτευμα [hierateuma], Священство [Svyashchenstvo]), Oriental Orthodox, Anglican, Assyrian, Old Catholic, Independent Catholic churches and some Lutheran churches Holy Orders comprise the three orders of bishop, priest and deacon, or the sacrament or rite by which candidates are ordained to those orders. Except for Lutherans and some Anglicans, these churches regard ordination as a sacrament (the sacramentum ordinis). The Anglo-Catholic party within Anglicanism tends to identify with the Roman Catholic position with regard to the sacramental nature of ordination.

Denominations have varied conceptions of Holy Orders. In the Anglican churches and some Lutheran churches the traditional orders of bishop, priest and deacon are bestowed using ordination rites. The extent to which ordination is considered sacramental in these traditions has, however, been a matter of some internal dispute. Many other denominations do not consider the role of ministry as being sacramental in nature and would not think of it in terms of "holy orders" as such. Historically, the word "order" (Latin ordo) designated an established civil body or corporation with a hierarchy, and ordinatio meant legal incorporation into an ordo. The word "holy" refers to the Church. In context, therefore, a holy order is set apart for ministry in the Church. Other positions such as pope, patriarch, cardinal, monsignor, archbishop, archimandrite, archpriest, protopresbyter, hieromonk, protodeacon, archdeacon, etc., are not sacramental orders. These are simply offices or titles.