| Union Jack | Union Jack |
| Union nationale des étudiants de France | Union nationale des étudiants de France |
| Union Pacific Railroad | Union Pacific Railroad |
| Union Parish | Union Parish |
| Unionen för fransk demokrati | Union pour la démocratie française |
| Unionen för nationernas Europa | Union für ein Europa der Nationen |
| Unionsflagga | Union Jack |
| Unionsmedborgarskapet | Unionsbürgerschaft |
| Unionsterritorium | Unionsterritorium |
| unisex | unisex |
| unisex- | Unisex- |
| Unisys | Unisys |
| UNITA | União Nacional para a Independência Total de Angola |
| unitarie | Unitarier |
| Unitarism | Unitarismus |
| United Airlines | United Airlines |
| United Fruit Company | Chiquita Brands International |
| United Group | United Group Limited |
| United Kingdom Independence Party | United Kingdom Independence Party |
| United Methodist Church | Evangelisch-methodistische Kirche |
| United Microelectronics Corporation | United Microelectronics Corporation |
| United Nations Emergency Force | United Nations Emergency Force |
| United Nations Environment Programme | Umweltprogramm der Vereinten Nationen |
| United Nations Framework Convention on Climate Change | Klimarahmenkonvention der Vereinten Nationen |
| United Nations Mission in Kosovo | United Nations Interim Administration Mission in Kosovo |
| United Nations Office on Drugs and Crime | United Nations Office on Drugs and Crime |
| United States Agency for International Development | United States Agency for International Development |
| United States Air Force | United States Air Force |
| United States Air Force Academy | United States Air Force Academy |
| United States Army | United States Army |
| United States Census Bureau | United States Census Bureau |
| United States dollar | United States Dollar |
| United States Military Academy | United States Military Academy |
| United States Navy Special Warfare Development Group | United States Naval Special Warfare Development Group |
| United States Soccer Federation | United States Soccer Federation |
| UNIVAC | Universal Automatic Calculator |
| Univers | Univers |
| Universal Binary | Universal Binaries |
| Universal Carrier | Universal Carrier |
| Universal Media Disc | Universal Media Disc |
