In certain Christian denominations, holy orders are the ordained ministries of bishop, priest (presbyter), and deacon, and the sacrament or rite by which candidates are ordained to those orders. Churches recognizing these orders include the Catholic Church, the Eastern Orthodox (ιερωσύνη [hierōsynē], ιεράτευμα [hierateuma], Священство [Svyashchenstvo]), Oriental Orthodox, Anglican, Assyrian, Old Catholic, Independent Catholic and some Lutheran churches. Except for Lutherans and some Anglicans, these churches regard ordination as a sacrament (the sacramentum ordinis).

Denominations have varied conceptions of holy orders. In Anglican and some Lutheran churches the traditional orders of bishop, priest and deacon are bestowed using ordination rites contained within ordinals. The extent to which ordination is considered sacramental in these traditions has, however, been a matter of some internal dispute. Baptists are among the denominations that do not consider 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 and archdeacon, are not sacramental orders but specialized ministries.