Churches of Christ affirm the classical Trinitarian doctrine, derived from Scripture alone, as a non-negotiable foundation of Christian faith. God is one, and he is Father, Son, and Holy Spirit — three distinct persons of the one divine being. Though Churches of Christ reject formal creeds as tests of fellowship, the Trinitarian understanding of God is universally affirmed across the fellowship.

Early Restoration Movement figures such as Alexander Campbell affirmed Trinitarian theology even while rejecting the language of 'persons' as unscriptural terminology. Contemporary Churches of Christ use Trinitarian language freely and regard the deity of Christ and the full personhood of the Spirit as clearly taught in Scripture.