In Christianity, a disciple is a dedicated follower of Jesus. This term is found in the New Testament only in the Gospels and Acts. Originating in the ancient Near East, the concept of a disciple is an adherent of a teacher. Discipleship is not the same as being a student in the modern sense; a disciple in the ancient biblical world actively imitated both the life and teaching of the master. It was a deliberate apprenticeship which made the fully formed disciple a living copy of the master.

The New Testament records many followers of Jesus during his ministry. Some disciples were given a mission, such as the Little Commission, the commission of the seventy in Luke's Gospel, the Great Commission after the resurrection of Jesus, or the conversion of Paul, making them apostles, charged with proclaiming the gospel (the Good News) to the world. Jesus emphasised that being his disciples would be costly.

The term "disciple" represents the Koine Greek word mathētḗs (μαθητής), which generally means "one who engages in learning through instruction from another, pupil, apprentice" or in religious contexts such as the Bible, "one who is rather constantly associated with someone who has a pedagogical reputation or a particular set of views, disciple, adherent." The word "disciple" comes into English usage by way of the Latin discipulus meaning a learner, but given its biblical background, should not be confused with the more common English word "student."

A disciple is different from an apostle, which instead means a messenger, more specifically "messengers with extraordinary status, especially of God's messenger, envoy." But predominately in the New Testament it is used of "a group of highly honored believers with a special function as God's envoys." While a disciple is one who learns and apprentices under a teacher or rabbi, an apostle is one sent as a missionary to proclaim the good news and to establish new communities of believers.

The meaning of the word "disciple" is not derived primarily from its root meaning or etymology but from its widespread usage in the ancient world. Disciples are found in the world outside of the Bible. For example among the ancient Greek philosophers, disciples learned by imitating the teacher's entire way of life and not just by remembering the spoken words of the teacher.

The first-century philosopher Seneca appeals to the "living voice and intimacy of common life" of the disciple–teacher relationship of many different philosophers:

Cleanthes could not have been the express image of Zeno, if he had merely heard his lectures; he also shared in his life, saw into his hidden purposes, and watched him to see whether he lived according to his own rules. Plato, Aristotle, and the whole throng of sages who were destined to go each his different way, derived more benefit from the character than from the words of Socrates.

In the world of the Bible, a disciple was a person who followed a teacher, or rabbi, or master, or philosopher. The disciple desired to learn not only the teaching of the rabbi, but to imitate the practical details of their life. A disciple did not merely attend lectures or read books, they were required to interact with and imitate a real living person. A disciple would literally follow someone in hopes of eventually becoming what they are.