Clerical marriage is the practice, followed in most Protestant churches, of allowing clergy to marry and have a family. This is in opposition to the doctrine of clerical celibacy currently followed in the Roman Catholic Church, where priests are not allowed to marry, on the principle that this leaves them free to devote their lives fully to the service of the Church and God. However, married priests have occasionally been allowed to transfer from other denominations - for example when a number of priests left the Church of England when it admitted women to the priesthood, and were granted entry to the Roman Catholic priesthood.

The tradition of clerical celibacy did not exist in the earliest church, and was not fully enforced even in the Middle Ages. The practice of clerical marriage was reinitiated in Wittenberg in 1521, inspired by the writings of Martin Luther. Luther himself, even though he was a monk, married Katharina von Bora, a nun, in 1525.

The Eastern churches never developed a tradition of enforced clerical celibacy, and parish priests are usually married. However, by tradition bishops are appointed from the clergy who have chosen to remain celibate, or from widowed clergy.