Social trinitarianism is a Christian interpretation of the Trinity as consisting of three persons, each person having their own center of consciousness. These persons are united in a loving relationship, which reflects a model for human relationships. The teaching emphasizes that God is an inherently social being. Human unity approaches conformity to the image of God's unity through self-giving, empathy, adoration for one another, etc. Such love is a fitting ethical likeness to God but is in stark contrast to God's unity of being. Those who are often associated with this term include Jürgen Moltmann, Miroslav Volf, Elizabeth Johnson, Leonardo Boff, John Zizioulas, William Lane Craig and Catherine LaCugna.

Social trinitarianism is often in contrast to Nicene trinitarianism, as social trinitarianism generally denies the trinity being defined primarily by the eternal relations of origin.

Some forms of social trinitarianism are opposed to Nicene Christianity in that they see the Trinity as composed of three distinct wills that voluntarily submit to one another, similarly to subordinationism.

Matthew Barret defines social trinitarianism thus:

Social trinitarianism is a diverse movement, which makes it difficult to define. But in its fully developed form, its starting point (or at least emphasis) is not simplicity—some reject simplicity—but the three persons. The Trinity is not defined primarily by eternal relations of origin. ST redefines the Trinity as a society and community analogous to a human society, redefines the persons as three centers of consciousness/will, redefines persons according to their relationships (focus on mutuality, societal interaction), and redefines unity as interpersonal relationships of love between persons (redefinition of perichoresis). ST collapses immanent and economic Trinity, sets East against West, and treats social Trinity as a paradigm for social theory (ecclesiology, politics, gender). ST has been adopted by modern theologians but is an abandonment/revision of Nicene orthodoxy.

By confessing that the Son is of the same essence as the Father (in other words, coessential and coeternal with the Father), the Nicene Creed defines the Trinity by 'eternal relations of origin', such as the eternal generation of the Son. The Son is not subordinate to the Father, nor is their relationship analogous to a human society in which the Son submits to the Father. This, along with subordinationism, are impossible in Nicene orthodoxy because all three persons of the Trinity are considered to be images of the very same being and will of God: thus, there is no will of the Son to submit to the Father, but rather one will which is threefold in image.

Orthodox Christian theology asserts that the one God exists in three 'persons' (this term was generally used in the Latin West). Social trinitarian thought argues that the three persons are each distinct realities—this was generally presented in the East with the Greek term 'hypostasis' from the First Council of Nicaea onward. Hypostasis was here employed to denote a specific individual instance of being. So, the Trinity is composed of three distinct 'persons' or 'hypostases' which are in integral relation with one another. The Cappadocian Fathers outlined the traditional set of doctrines describing the relational character of the Trinity: the Father is the Father by virtue of begetting the Son; likewise the Son is the Son precisely by being begotten. These two hypostases do not have their identity first as individual entities that then relate; rather, they are what they are precisely due to their relations. John Zizioulas is perhaps the best-known contemporary proponent of this emphasis in trinitarian theology, which he labels relational ontology.

Many proponents of the social trinitarianism, including John Zizioulas, criticize modern individualism by mapping human relationships onto this relational ontology as well. This suggests that the individual is not constituted over and against other persons. On the contrary, say these proponents, a person's identity and self are deeply constituted by their relationships, such that a person could not be the same person were it not for the relationship - the relationship, in some sense at least, precedes (ontologically, though not necessarily temporally) the person rather than the person preceding the relationship.