‘Participation’ or ‘partaking’ has featured in Christian theology since the New Testament, describing a relation of derivation, likeness, or communion. Theologians including Gregory of Nyssa, Augustine of Hippo, Pseudo-Dionysius, Maximus the Confessor, and Thomas Aquinas made this theme an important aspect of their work. In marked but more limited ways, participation was also important for Martin Luther, John Calvin, and later Protestant writers. With themes of sharing and reception from a transcendent source, Christian theologians have found common ground with Platonism. A wide range of topics in Christian theology have been explored in these terms. While each can be set out in relative isolation, participation lends itself to an integrative view. As the backbone for a scheme of theological metaphysics, participation has come to renewed prominence in the second half of the twentieth century. Today it offers an area of considerable shared interest, across ecclesial traditions.