Union Theological Seminary may refer to:

• Union Theological Seminary in the City of New York, an ecumenical seminary affiliated with Columbia University in Manhattan
• Union Theological Seminary & Presbyterian School of Christian Education, in Richmond, Virginia

Neither of these two "Union" seminaries should be confused with the following seminaries:

• United Theological Seminary of the Twin Cities in New Brighton, Minnesota, affiliated with the United Church of Christ
• United Theological Seminary in Dayton, Ohio, affiliated with the United Methodist Church
• Unification Theological Seminary in Barrytown, New York, affiliated with the Unification Church