The hierarchy of the Catholic Church consists of its bishops, priests, and deacons. In the ecclesiological sense of the term, "hierarchy" strictly means the "holy ordering" of the church, the Body of Christ, so to respect the diversity of gifts and ministries necessary for genuine unity.

In canonical and general usage, it refers to those who exercise authority within a Christian church. In the Catholic Church, authority rests chiefly with bishops, while priests and deacons serve as their assistants, co-workers or helpers. Accordingly, "hierarchy of the Catholic Church" is also used to refer to the bishops alone. The term "pope" was still used loosely until the sixth century, being at times assumed by other bishops. The term "hierarchy" became popular only in the sixth century, due to the writings of Pseudo-Dionysius.

As of 31 December 2020, the Catholic Church consisted of 2,903 dioceses or equivalent jurisdictions, each overseen by a bishop. Dioceses are divided into individual communities called parishes, each staffed by one or more priests, deacons, or lay ecclesial ministers. Ordinarily, care of a parish is entrusted to a priest, though there are exceptions. Approximately 19.3% of all parishes do not have a resident pastor, and 1,948 parishes worldwide are entrusted to a deacon or lay ecclesial minister.

All clergy, including deacons, priests, and bishops, may preach, teach, baptize, witness marriages, and conduct funeral liturgies. Only priests and bishops can celebrate the sacraments of the Eucharist (though others may be ministers of Holy Communion), Penance (Reconciliation, Confession), Confirmation (priests may administer this sacrament with prior ecclesiastical approval), and Anointing of the Sick. Only bishops can administer the sacrament of Holy Orders, by which men are ordained as bishops, priests or deacons.

The existence of a Roman Catholic hierarchy (made of bishops, priests, and deacons) is attested since the time of the first Epistle of Ignatius to the Philadelphians.

The bishops, who possess the fullness of orders, and therefore the fullness of both priesthood and diaconate, are as a body (the College of Bishops) considered the successors of the Apostles and are "constituted Pastors in the Church, to be the teachers of doctrine, the priests of sacred worship and the ministers of governance" and "represent the Church." In 2012, there were 5,133 Catholic bishops; at the end of 2021, there were 5,340 Catholic bishops. The Pope himself is a bishop (the bishop of Rome) and traditionally uses the title "Venerable Brother" when writing formally to another bishop.

The typical role of a bishop is to provide pastoral governance for a diocese. Bishops who fulfill this function are known as diocesan ordinaries, because they have what canon law calls ordinary (i.e. not delegated) authority for a diocese. These bishops may be known as hierarchs in the Eastern Catholic Churches. Other bishops may be appointed to assist ordinaries (auxiliary bishops and coadjutor bishops) or to carry out a function in a broader field of service to the church, such as appointments as papal nuncios or as officials in the Roman Curia.

Bishops of a country or region may form an episcopal conference and meet periodically to discuss current problems. Decisions in certain fields, notably liturgy, fall within the exclusive competence of these conferences. The decisions of the conferences are binding on the individual bishops only if agreed to by at least two-thirds of the membership and confirmed by the Holy See.