In Christianity, an archbishop is an elevated bishop heading a diocese of particular importance due to either its size, history, or both, called an archdiocese. When a bishop becomes an archbishop, he is not in any sense being ordained nor otherwise receiving any sacrament; by contrast (in the Anglican, Catholic, and Orthodox churches) a man becoming a bishop is being consecrated.

Archbishops do not necessarily have more power than bishops, but they are in charge of more prestigious dioceses. However, many archbishops are also the metropolitans of the ecclesiastical province in which their archdiocese is located. In Western churches (i.e. Roman Catholic or Anglican), this is almost always the case. However, in Roman Catholicism, archbishops who are not metropolitans are styled Archbishop ad personam, and do not receive the right to wear the pallium. In the Slavic Eastern churches (both Catholic and Orthodox) archbishops and metropolitans are distinct, although a metropolitan may be referred to as metropolitan archbishop. In the Greek Orthodox Church, archbishops outrank metropolitans, and have the same rights as Slavic (Eastern) Orthodox metropolitans. The Oriental Orthodox generally follow the pattern of the Slavic Orthodox with respect to the archbishop/metropolitan distinction.

Etymology: From Greek archepiskopos: arche, first, and epi-skopos, over-seer or supervisor.