A pastor (abbreviated to "Ps","Pr", "Pstr.", "Ptr." or "Psa" (both singular), or "Ps" (plural)) is the leader of a Christian congregation who also gives advice and counsel to people from the community or congregation. In Lutheranism, Catholicism, Eastern Orthodoxy, Oriental Orthodoxy and Anglicanism, pastors are always ordained. In Methodism, pastors may be either licensed or ordained.

The New Testament typically uses the words "bishops" (Acts 20:28) and "presbyter" (1 Peter 5:1) to indicate the ordained leadership in early Christianity. However, the word "pastor" (ποιμήν/poimēn) is only used one time to describe church leadership in the New Testament in Ephesians 4:11 which says, "that some would be apostles, some prophets, some evangelists, some pastors and teachers" (NRSV). Peter instructs church leadership using the verb, "to tend the flock' (lit. 'to shepherd,' ποιμαίνω/poimainō) of God that is in your charge, exercising the oversight (1 Peter 5:2 NRSV). The words "bishop" and "presbyter" were sometimes used in an interchangeable way, such as in Titus 1:5-6. However, there is ongoing dispute between branches of Christianity over whether there are two ordained classes (presbyters and deacons), or three (bishops, priests, and deacons). The first view is affirmed by some Presbyterians. On the other hand, Christians of the Roman Catholic, Persian, Eastern Orthodox, Oriental Orthodox, Moravian, Scandinavian Lutheran, Anglican, Old Catholic and other Presbyterian traditions maintain the latter view, with all but the Presbyterians affirming the doctrine of apostolic succession.

These terms describe a leader (e.g., bishop), one who maintains a careful watch for the spiritual needs of all the members of the flock (i.e., a pastor). The person must meet scriptural qualifications (1 Timothy 3:1-7; Titus 1:5-9). For some Protestants, whether called an elder, bishop, or pastor, these terms describe the same service in the church. In the early Church, only a man could be a presbyter, but many Protestant denominations in the 19th and 20th century have changed to allow women to be pastors, though others retained a male presbyterate. Whether man or woman, this person is to be older and experienced in the faith (i.e., an elder), a person who is a decision-maker, and a manager of church affairs.

The actual word pastor is derived from a Latin word meaning "shepherd".

The word "pastor" derives from the Latin noun pastor which means "shepherd" and is derived from the verb pascere – "to lead to pasture, set to grazing, cause to eat". The term "pastor" also relates to the role of elders within the New Testament, and is synonymous with the biblical understanding of the word "minister". Amongst contemporary Protestant Christians, terms pastor, shepherd, and elder are all the same position.

Present-day usage of the word is rooted in the Biblical metaphor of shepherding. The Hebrew Bible (or Old Testament) uses the Hebrew word רעה (roʿeh), which is used as a noun as in "shepherd", and as a verb as in "to tend a flock." It occurs 173 times in 144 Old Testament verses and relates to the literal feeding of sheep, as in Genesis 29:7. In Jeremiah 23:4, both meanings are used (ro'im is used for "shepherds" and yir'um for "shall feed them"), "And I will set up shepherds over them which shall feed them: and they shall fear no more, nor be dismayed, neither shall they be lacking, saith the LORD." (KJV).

English-language translations of the New Testament usually render the Greek noun ποιμήν (poimēn) as "shepherd" (18x) and the Greek verb ποιμαίνω (poimainō) as "to herd [a flock], shepherd" (11x). The two words occur a total of 29 times in the New Testament, often referring to Jesus (11x). Most notably in John 10, Jesus called himself the "Good Shepherd" in John 10:11. The same words in the familiar Christmas story (Luke 2) refer to literal shepherds.

In five New Testament passages though, the words relate to members of the church: