The Lutheran Church—Missouri Synod affirms the classical doctrine of the Trinity as taught in the Book of Concord (1580), the confessional standard of Lutheranism. God is one in essence and three in person—Father, Son, and Holy Spirit—coequal, coeternal, and consubstantial. This doctrine stands in continuity with the Nicene Creed and the Chalcedonian definition and is considered fundamental to Christian orthodoxy.

The LCMS teaches that the filioque clause (the Holy Spirit proceeds from the Father and the Son) is a legitimate interpretation of Scripture and tradition, placing it within the Western (Latin) Christian tradition. The three persons of the Trinity possess all the divine attributes equally and are equally worthy of worship and adoration.

This Trinitarian doctrine is essential to LCMS theology and catechesis. Denial of the Trinity or the full divinity and personhood of any member of the Godhead is regarded as heresy incompatible with Lutheran confession.