Nondenominational Christianity (or non-denominational Christianity) consists of churches which typically distance themselves from the confessionalism or creedalism of other Christian communities  by not formally aligning with a specific Protestant denomination. Often founded by individual pastors, they have little affiliation with historic denominations, but typically adhere to evangelical Protestantism, and are a type of Protestantism.   
Nondenominational and interdenominational missionary organizations, especially faith missions, grew in the second half of the 19th century, beginning with the Woman's Union Missionary Society (incorporated in the United States in 1861) and the China Inland Mission (incorporated in Britain in 1865).  Later-founded U.S. missionary groups included Christian and Missionary Alliance (1887), Evangelical Alliance Mission (1890), Sudan Interior Mission (1893), and the Africa Inland Mission (1895). 
Nondenominational congregations experienced significant and continuous growth in the 21st century, particularly in the United States.   If combined into a single group, nondenominational churches collectively represented the third-largest Christian grouping in the United States in 2010, after the Roman Catholic Church and Southern Baptist Convention. 
Nondenominational churches are not affiliated with specifically denominational stream of evangelical movements, either by choice from their foundation or because they separated from their denomination of origin at some point their history.  Like denominational congregations, nondenominational congregations vary in size, worship, and other characteristics.  Although independent, many nondenominational congregations choose to affiliate with a broader network of congregations, such as IFCA International (formerly the Independent Fundamental Churches of America). 
Churches with a focus on seekers are more likely to identify themselves as nondenominational. 
Boston University religion scholar Stephen Prothero argues that nondenominationalism hides the fundamental theological and spiritual issues that initially drove the division of Christianity into denominations behind a veneer of "Christian unity". He argues that nondenominationalism encourages a descent of Christianity—and indeed, all religions—into comfortable "general moralism" rather than being a focus for facing the complexities of churchgoers' culture and spirituality. Prothero further argues that it also encourages ignorance of the Scriptures, lowering the overall religious literacy while increasing the potential for inter-religious misunderstandings and conflict. 
Baptist ecumenical theologian Steven R. Harmon argues that "there's really no such thing" as a nondenominational church, because "as soon as a supposedly non-denominational church has made decisions about what happens in worship, whom and how they will baptize, how and with what understanding they will celebrate holy communion, what they will teach, who their ministers will be and how they will be ordered, or how they relate to those churches, these decisions have placed the church within the stream of a specific type of denominational tradition."  Harmon argues that the cause of Christian unity is best served through denominational traditions, since each "has historical connections to the church's catholicity ... and we make progress toward unity when the denominations share their distinctive patterns of catholicity with one another." 
Presbyterian dogmatic theologian Amy Plantinga Pauw writes that Protestant nondenominational congregations "often seem to lack any acknowledgement of their debts and ties to larger church traditions" and argues that "for now, these non-denominational churches are living off the theological capital of more established Christian communities, including those of denominational Protestantism."  Pauw considers denominationalism to be a "unifying and conserving force in Christianity, nurturing and carrying forward distinctive theological traditions" (such as Wesleyanism being supported by Methodist denominations). 
- Protestantism in the United States
- History of Protestantism in the United States
- Community Church movement
- Local churches
- Non-church movement
- Non-denominational Muslim
- Non-denominational Judaism
- Sunday Christian
- Confessionalism is a term employed by historians to refer to "the creation of fixed identities and systems of beliefs for separate churches which had previously been more fluid in their self-understanding, and which had not begun by seeking separate identities for themselves—they had wanted to be truly Catholic and reformed." (MacCulloch, The Reformation: A History, p. xxiv.)
- Allan Anderson, An Introduction to Pentecostalism: Global Charismatic Christianity, Cambridge University Press, UK, 2013, p. 157
- "Appendix B: Classification of Protestants Denominations". Pew Research Center - Religion & Public Life / America's Changing Religious Landscape. Retrieved 13 October 2019.
- Nondenominational Congregations Research at Hartford Institute for Religion Research website. Hirr.hartsem.edu. Retrieved on 2010-11-03.
- Roger E. Olson, The Mosaic of Christian Belief, InterVarsity Press, USA, 2016, p. 43
- Norman E. Thomas, Missions and Unity: Lessons from History, 1792—2010 (Cascade Book, 2010), pp. 35, 42.
- Michael De Groote, The rise of the nons: Why nondenominational churches are winning over mainline churches, deseretnews.com, USA, February 25, 2011
- Vincent Jackson, How non-denominational churches are attracting millennials, pressofatlanticcity.com, USA, February 2, 2017
- Nondenominational & Independent Congregations, Hartford Seminary, Hartford Institute for Religion Research.
- Peter C. Phan, Christianities in Asia, John Wiley & Sons, USA, 2011, p. 90-91
- Gabriel Monet, L'Église émergente : être et faire Église en postchrétienté, LIT Verlag Münster, Switzerland, 2013, p. 135-136
- Nicole K. Meidinger & Gary A. Goreharm, "Congregations, Religious" in Encyclopedia of Community: From the Village to the Virtual World (Vol. 1: eds Karen Christensen & David Levinson: SAGE, 2003), p. 333.
- Pew Research Center, AMERICA'S CHANGING RELIGIOUS LANDSCAPE, pewforum.org, USA, May 12, 2015
- Ed Stetzer, The rise of evangelical 'nones', cnn.com, USA, June 12, 2015
- Peter C. Phan, Christianities in Asia, John Wiley & Sons, USA, 2011, p. 90
- Sébastien Fath, Dieu XXL, la révolution des mégachurches, Édition Autrement, France, 2008, p. 25, 42
- Bryan S. Turner, Oscar Salemink, Routledge Handbook of Religions in Asia, Routledge, UK, 2014, p. 407
- Allan Anderson, An Introduction to Pentecostalism: Global Charismatic Christianity, Cambridge University Press, UK, 2013, p. 66
- Kimon Howland Sargeant, Seeker Churches: Promoting Traditional Religion in a Nontraditional Way, Rutgers University Press, USA, 2000, p. 28
- Prothero, Stephen (2007). Religious Literacy: What Every American Needs to Know - and Doesn't. New York: HarperOne. ISBN 0-06-084670-4.
- Steven R. Harmon, Ecumenism Means You, Too: Ordinary Christians and the Quest for Christian Unity (Cascade Books, 2010), pp. 61-62.
- Amy Plantinga Pauw, "Earthen Vessels: Theological Reflections on North American Denominationalism" in Theology in Service to the Church: Global and Ecumenical Perspectives (ed. Allan Hugh Cole: Cascade Books, 2014), p. 82.