The overwhelming majority of non-denominational evangelical churches affirm Trinitarian orthodoxy: one God eternally existing in three co-equal, co-eternal persons — Father, Son, and Holy Spirit. Most non-denominational evangelical statement-of-faith documents explicitly confess the Trinity as a foundational, non-negotiable doctrine. Many draw from historic evangelical confessions or produce their own local statements that mirror the Nicene Creed's Trinitarian affirmations.

Because non-denominational evangelicalism is not governed by a single confessional body, there is no single authoritative document. However, broad surveys of non-denominational church statement of faith documents (as compiled by researchers such as those associated with the National Association of Evangelicals or Pew Research Center) show near-universal Trinitarian affirmation. The Trinity is typically presented as the starting point for all other doctrine.

A small minority of congregations that self-identify as 'non-denominational' or 'interdenominational' may hold non-Trinitarian views (e.g., Oneness theology, modalism), but these represent outliers rather than the mainstream of the movement. The typical non-denominational evangelical church that calls itself such in the United States affirms classical Trinitarian doctrine.