All Souls Church, Unitarian is a Unitarian Universalist congregation in Washington, D.C., chartered in 1821 as the First Unitarian Church of Washington and renamed All Souls in 1877. Its current building at 16th and Harvard Streets NW, modeled on St Martin-in-the-Fields in London, was completed in 1924 and listed on the National Register of Historic Places in 2020. The congregation is noted for its civil rights history, including its role in Washington's mid-20th-century social justice movements.