The trinitarian formula is the phrase "in the name of the Father, and of the Son, and of the Holy Spirit", or words to that form and effect.

These words are quoted in literal conformity to a command of Jesus according to the Bible, commonly called the Great commission of Matthew 28:19: " Therefore go and make disciples of all nations, baptizing them in [or into] the name of the Father and of the Son and of the Holy Spirit."

According to Roman Catholicism, Eastern Orthodoxy, and most forms of Protestantism, a baptism is not valid if the trinitarian formula is not used in the administration of that sacrament. Consequently, religious communities that baptize without the trinitarian formula are not presumed to be Christian religions. The formula is also used in other prayers, rites, liturgies, and Catholic sacraments.

From the late twentieth century onwards, many Christians have become uncomfortable with the traditionally male representation of God and have sought to de-emphasise or eliminate altogether gender-specific references to God. Some of these indiviuals and groups prefer the formula "in the name of the Creator, the Redeemer, and the Sanctifier". Other Christians point out that all persons of the Trinity are involved in creation, redemption, and sanctification, and that attempting to redefine the Trinity in terms of "functions" is essentially a form of modalism.

See also: Holy Trinity,