The doctrine of God’s Triunity is at the core of Christian faith; this article presents a theological survey of how it has been understood in a musical way during the Christian era. The role of music as a participation in the liturgy of mutual love eternally experienced in the Trinity is first analyzed, with references to the Church Fathers and to modern/contemporary theologians. Later, the three main forms of congregational singing are taken into account (i.e., monody, polyphony and harmony), pointing out how each has been seen in turn as a symbol of the Trinity’s love.