The Lutheran Church – Missouri Synod (LCMS), also known as the Missouri Synod, is an orthodox, traditional, confessional Lutheran denomination in the United States. With 1.8 million members as of 2021, it is the second-largest Lutheran body in the United States, behind the Evangelical Lutheran Church in America. The LCMS was organized in 1847 at a meeting in Chicago, Illinois, as the German Evangelical Lutheran Synod of Missouri, Ohio, and Other States, a name which partially reflected the geographic locations of the founding congregations.

Confessional Lutheranism is a name used by Lutherans to designate those who believe in the doctrines taught in the Book of Concord of 1580 in their entirety. Confessional Lutherans maintain that faithfulness to the Book of Concord, which is a summary of the teachings found in Scripture, requires attention to how that faith is actually being preached, taught, and put into practice. Confessional Lutherans believe that this is a vital part of their identity as Lutherans.