The baptism of Jesus by John the Baptist is a major event in the life of Jesus which is described in the three synoptic Gospels of the New Testament (Matthew, Mark and Luke), in which John ritually purified Jesus with water. It is considered to have taken place at Al-Maghtas (also called Bethany Beyond the Jordan), today located in Jordan.

Modern biblical scholars view the baptism of Jesus as a historical event to which a high degree of certainty can be assigned. Along with the crucifixion of Jesus, biblical scholars view it as one of the two historically certain facts about him, and often use it as the starting point for the study of the historical Jesus.

The baptism is one of the events in the narrative of the life of Jesus in the canonical Gospels; others include the Transfiguration, Crucifixion, Resurrection, and Ascension. Most Christian denominations view the baptism of Jesus as an important event and a basis for the Christian rite of baptism (see also Acts 19:1–7). In Eastern Christianity, Jesus's baptism is commemorated on 6 January (the Julian calendar date of which corresponds to 19 January on the Gregorian calendar), the feast of Epiphany. In the Roman Catholic Church, the Anglican Communion, the Lutheran Churches and some other Western denominations, it is recalled on a day within the following week, the feast of the baptism of the Lord. In Roman Catholicism, the baptism of Jesus is one of the Luminous Mysteries sometimes added to the Rosary. It is a Trinitarian feast in the Eastern Orthodox Churches.