The idea of congregational self-governance developed on this continent because the Puritans who arrived from Europe wanted to have responsibility for their own churches, not to have bishops dictate their practices. The church structures the colonists knew best were hierarchical; they were familiar with the Episcopal structure, where bishops and archbishops have the final word, and with the Presbyterian structure, a form of representative democracy where a body of elected representatives holds authority over the churches. They rejected hierarchical forms and adopted a different structure, the congregational system of governance, which requires each church or congregation to be independently governed and to make its own decisions in such major areas as:

• Defining membership requirements
• Electing leadership, including calling and dismissing ministers
• Purchase or sale of property.

In the matter of governance, Unitarian Universalist congregations today are directly descended from the Puritan churches that were self-governing. Each congregation has title to its property. No official in a religious hierarchy may close a Unitarian Universalist congregation, or fire its minister. No authority outside the congregation can define membership or dictate the annual budget of the congregation. Only the members of the congregation can make such determinations. This structure of self-government is called congregational polity.

While members cannot be consulted on every decision, they do vote on the most important issues. One of the important decisions is the election of leaders, generally a governing board and the call of the minister(s). Implicit in our congregational covenants is a promise to trust leaders to make decisions within particular realms, and to ask when they need guidance. For example, ministers generally have responsibility for worship-related concerns, though some issues such as adding an extra worship service may require a congregational vote, or certainly, input. A religious educator or Religious Education Committee may create a Coming of Age program for youth, but the congregation will determine when a youth may become a member of the congregation.

Membership means that you are able to help make the important decisions. The members collectively own the congregation and are vested with the power of governance. Elected lay leaders and called ministers are accountable to the congregation.

Relationships between congregations are mutual relationships of equals, regardless of the congregations' size or influence. Unitarian Universalist congregations covenant to form the Unitarian Universalist Association of congregations, coming together for mutual benefit. Together, we can do what would be difficult for any but the very largest congregations alone, such as:

• Create religious education curricula for all ages
• Develop hymnbooks and other worship resources
• Accredit ministers and other religious professionals
• Assist congregations in searching for ministers and other religious professionals
• Support the education of both lay people and religious professionals
• Help determine best practices in religious life
• Take action to support or oppose national social issues
• Publish books (Skinner House Press and Beacon Press)
• Create brochures and pamphlets to promote Unitarian Universalism
• Help in cases of trauma or crisis, such as natural disasters
• Develop relations with Unitarians and Universalists around the world
• Interact with other faith communities
• Serve as a nexus of electronic communication for Unitarian Universalists with shared interests.

Unitarian Universalist congregations also participate in Districts, geographic groupings of congregations which work together to promote Unitarian Universalism and to support one another. Clusters are smaller groups of congregations within a District.