Union Theological Seminary is a Christian seminary in New York that is affiliated with Columbia University.

Union Theological Seminary may also refer to:

• Guangdong Union Theological Seminary, a Protestant seminary in Guangzhou, Guangdong, China
• Nanjing Union Theological Seminary, a Protestant seminary in Jiangsu, China
• Tokyo Union Theological Seminary, a Protestant seminary in Japan
• Union Presbyterian Seminary or Union Theological Seminary in Virginia and Presbyterian School of Christian Education, in Richmond, Virginia, and Charlotte, North Carolina
• Union Theological Seminary (Philippines), a Protestant seminary in Dasmariñas, Cavite, Philippines

• Albright College, formerly known as Union Seminary, a college in Reading, Pennsylvania
• Union Biblical Seminary in Pune, India
• Union School of Theology, Wales
• United Theological Seminary in Dayton, Ohio, affiliated with the United Methodist Church
• United Theological Seminary of the Twin Cities in New Brighton, Minnesota, affiliated with the United Church of Christ
• Unification Theological Seminary in Barrytown, New York, affiliated with the Unification Church
• Union College (disambiguation)
• Union Theological College, Belfast
• Union University (disambiguation)