Baptism is a Christian sacrament of initiation almost invariably with the use of water. It may be performed by sprinkling or pouring water on the head, or by immersing in water either partially or completely, traditionally three times, once for each person of the Trinity. The synoptic gospels recount that John the Baptist baptised Jesus. Baptism is considered a sacrament in most churches, and as an ordinance in others. Baptism according to the Trinitarian formula, which is done in most mainstream Christian denominations, is seen as being a basis for Christian ecumenism, the concept of unity amongst Christians. Baptism is also called christening, although some reserve the word "christening" for the baptism of infants. In certain Christian denominations, such as the Catholic Churches, Eastern Orthodox Churches, Oriental Orthodox Churches, Assyrian Church of the East, and Lutheran Churches, baptism is the door to church membership, with candidates taking baptismal vows. It has also given its name to the Baptist churches and denominations.

ખ્રિસ્તી ધર્મમાં, બાપ્તિસ્મા (બૅપ્ટિઝમ) એ પાણીના ઉપયોગથી કરવામાં આવતી ધાર્મિક વિધિ છે, જેના થકી વ્યક્તિને દેવળના સભ્ય તરીકે સ્વીકૃતિ આપવામાં આવે છે. નવા કરાર મુજબ ખુદ ઈસુને પણ બાપ્તિસ્મા આપવામાં આવ્યા હતા.