The United Church of Christ (UCC) is a mainline Protestant Christian denomination principally in the United States, generally considered within the Reformed tradition, and formed in 1957 by the union of two denominations, the Evangelical and Reformed Church and the Congregational Christian Churches.

According to the 2007 yearbook, the United Church of Christ has approximately 1.2 million members and is composed of approximately 5,518 local congregations.

Although similar in name, the UCC denomination is theologically and, for the most part, historically distinct from the Churches of Christ, a loose affiliation of conservative congregations that arose primarily from the Stone-Campbell Restoration Movement in the 19th century.