Jehovah's Witnesses is a millenarian restorationist Christian denomination with nontrinitarian beliefs distinct from mainstream Christianity. The group reports a worldwide membership of approximately 8.5 million adherents involved in evangelism and an annual Memorial attendance of over 19.7 million. Jehovah's Witnesses are directed by the Governing Body of Jehovah's Witnesses, a group of elders in Warwick, New York, United States, which establishes all doctrines based on its interpretations of the Bible. They believe that the destruction of the present world system at Armageddon is imminent, and that the establishment of God's kingdom over the earth is the only solution for all problems faced by humanity.

The group emerged from the Bible Student movement founded in the late 1870s by Charles Taze Russell, who also co-founded Zion's Watch Tower Tract Society in 1881 to organize and print the movement's publications. A leadership dispute after Russell's death resulted in several groups breaking away, with Joseph Franklin Rutherford retaining control of the Watch Tower Society and its properties. Rutherford made significant organizational and doctrinal changes, including adoption of the name Jehovah's witnesses in 1931 to distinguish them from other Bible Student groups and symbolize a break with the legacy of Russell's traditions.

Jehovah's Witnesses are known for their door-to-door preaching, distributing literature such as The Watchtower and Awake!, and for refusing military service and blood transfusions. They consider the use of God's name vital for proper worship. They reject Trinitarianism, inherent immortality of the soul, and hellfire, which they consider to be unscriptural doctrines. They do not observe Christmas, Easter, birthdays or other holidays and customs they consider to have pagan origins incompatible with Christianity. They prefer to use their own Bible translation, the New World Translation of the Holy Scriptures, although their literature occasionally quotes and cites other Bible translations. Adherents commonly refer to their body of beliefs as "The Truth" and consider themselves to be "in the Truth". They consider "human society" to be morally corrupt and under the influence of Satan, and most limit their social interaction with non-Witnesses. Congregational disciplinary actions include disfellowshipping, their term for formal expulsion and shunning, a last resort for what they consider serious offenses. Baptized individuals who formally leave are considered disassociated and are also shunned. Disfellowshipped and disassociated individuals may eventually be reinstated if deemed repentant.

The group's position regarding conscientious objection to military service and refusal to salute state symbols (like national anthems and flags) has brought it into conflict with some governments. Consequently, some Jehovah's Witnesses have been persecuted and their activities are banned or restricted in some countries. Persistent legal challenges by Jehovah's Witnesses have influenced legislation related to civil rights in several countries.

The organization has received criticism regarding biblical translation, doctrines, and alleged coercion of its members. The Watch Tower Society has made various unfulfilled predictions about major biblical events such as Christ's Second Coming, the advent of God's kingdom, and Armageddon. Their policies for handling cases of child sexual abuse have been the subject of various formal inquiries.