A non-denominational church (usually Christian) is a religious organization which does not necessarily align its mission and teachings to an established denomination. It is also often done to allow the church to govern themselves without interference from the policies of a regional, national or multinational organization, in regards to budgets, memberships, policies, formal standards, and public image. Additionally, some religious bodies consciously reject the idea of a denominational structure as a matter of doctrine, insisting that each congregation be autonomous. Examples of fellowships of this sort include Independent Christian Churches, Open Bible Standard Churches, and the Church of Christ. However, while these groups reject the trappings of a formal denominational structure, they are widely regarded and referred to as denominations simply because they are a grouping of congregations with similar beliefs and practices. To their own members, they are "non-denominational", but they are not what is generally meant when discussion of non-denominational churches is undertaken.

Non-denominational churches are often more accepting of people from various religious backgrounds and more tolerant of differing religious, political or moral viewpoints. Critics feel however, that there cannot be a truly "non-denominational" church as all churches adhere to a core set of beliefs, though that set of beliefs may not be formalized as specific denomination. Likewise, an independent church with strongly fundamentalist and/or evangelical leanings may describe itself as "non-denominational" in order to give the impression of being generically Christian, or that no Christian has any business disagreeing with its teachings. In the strict sense of the definition, a non-denominational organization itself is a denomination. While many non-denominational churches may be indistinguishable from an established denomination in teachings, they are usually free to change those teachings to better suit the church members, free of strict policies set down by a parent organization.

In the United States, the number of evangelical non-denominational churches (often included in the category of American Protestantism) has increased exponentially since the late 1950s. Many historians of American religion cite after-effects of the Scopes Trial and Baby Boomers, as well as the higher standard of living available in the United States, and the movement away from authority in American culture due to Watergate and other scandals.

According to research by Barna Research and others there is an increase in the number of Christians who do not align themselves with any denomination. Many of these attend city or regional "super" or "mega" churches of congregations of 1500+ attendees.