First Unitarian Society usually designates a humanist Unitarian/Unitarian Universalist congregation, and may refer to:
- First Unitarian Society, Minneapolis, established 1881, birthplace of religious humanism
- First Unitarian Society in Newton, Massachusetts (1906)
- First Unitarian Society Meetinghouse, Shorewood Hills, Madison, Wisconsin (1951), a National Historic Landmark and NRHP-listed