Union Treaty

Union Treaty may refer to:
 * Treaty on the Creation of the Union of Soviet Socialist Republics (1922)
 * New Union Treaty (1991), proposed treaty on the creation of the Union of Soviet Sovereign Republics or the Union of Sovereign States
 * Treaty on European Union (1992/2007)
 * Treaty of Union (1707), creating the Kingdom of Great Britain
 * Treaty of Union (1790), creating the United States of Belgium