| United Nations Security Council Resolution 662 | United Nations Security Council Resolution 678 | United Nations Security Council Resolution 681 |
| United Nations Security Council Resolution 687 | United Nations Security Council Resolution 694 | United Nations Security Council Resolution 726 |
| United Nations Security Council Resolution 799 | United Nations Supervision Mission in Syria | United Nations Support Mission in Libya |
| United Nations Transitional Administration in East Timor | United Parcel Service | United Press International |
| United Principalities | United Provinces of Central Italy | United Russia |
| United States | United States Adopted Name | United States Africa Command |
| United States Air Force | United States Air Force Academy | United States Air Force Thunderbirds |
| United States Army | United States Atomic Energy Commission | United States Attorney |
| United States bombing of the Chinese embassy in Belgrade | United States box office records | United States Census Bureau |
| United States Census, 2000 | United States Census, 2010 | United States Coast Guard |
| United States Conference of Catholic Bishops | United States Congress | United States Constitution |
| United States copyright law | United States Cultural Exchange Programs | United States customary units |
| United States Department of Agriculture | United States Department of Defense | United States Department of Energy |
| United States Department of Health and Human Services | United States Department of State | United States Department of Veterans Affairs |
| United States diplomatic cables leak | United States dollar | United States Environmental Protection Agency |
| United States fiscal cliff | United States Fish and Wildlife Service | United States Geological Survey |
| United States Holocaust Memorial Museum | United States House of Representatives | United States Medical Licensing Examination |
| United States Military Academy | United States National Academy of Sciences | United States National Library of Medicine |
| United States national missile defense | United States Navy | United States occupation of the Dominican Republic (1965–66) |
| United States of Africa | United States of America | United States Olympic Committee |
| United States passport | United States Pharmacopeia | United States Poet Laureate |
| United States presidential election, 2016 | United States Secretary of Commerce | United States Secretary of the Treasury |
| United States Senate | United States Senate Committee on Environment and Public Works | United States Senate Committee on Foreign Relations |
| United States Senate Committee on Veterans' Affairs | United States Supreme Court | United States Virgin Islands |
| United States women's national soccer team | United States-Iran relations | United we stand, divided we fall |
| United World College Maastricht | United World College of the Adriatic | United World Colleges |
| Unitrans | Units of information | Units of measurement |
| Units of textile measurement | Unity (game engine) | Unity (logiciel) |
| Unity (user interface) | Unity Cooperative Company | Unity Linux |
| Unity Village, Missouri | Unity, Clark County, Wisconsin | Unity, Oregon |
| Unity, Trempealeau County, Wisconsin | Unity, Wisconsin | Universal (metaphysics) |
| Universal algebra | Universal approximation theorem | Universal Declaration of Human Rights |
| Universal design | Universal Disk Image Format | Universal gateway |
| Universal grammar | Universal Media Disc | Universal monarchy |
| Universal Music Group | Universal Pictures | Universal Plug and Play |
| Universal property | Universal Serial Bus | Universal set |
| Universal Soldier (1992 film) | Universal Soldier: Day of Reckoning | Universal space |
| Universal Studios | Universal Time | Universalism |
| Universality (philosophy) | Universality–diversity paradigm | Universe |
| Universita Cattolica del Sacro Cuore | Universitas 21 | Universitat zu Wien |
| Université Hassiba Ben Bouali chlef | Université islamique de Say | Universities & Colleges Admissions Service |
| University | University City, Missouri | University College Dublin A.F.C. |
| University College of Opera | University Heights, Iowa | University of al-Jazirah |
| University of al-Qarawiyyin | University of Belgrade | University of Berne |
| University of Birmingham | University of Bologna | University of Bolton |
| University of British Columbia | University of Cairo | University of California |
| University of California Press | University of California, Berkeley | University of California, Irvine |
| University of California, Santa Barbara | University of Cambridge | University of Castilla–La Mancha |
| University of Chicago | University of Colorado Boulder | University of Colorado Denver |
| University of Debrecen | University of Denver | University of Dundee |
| University of Engineering and Technology, Lahore | University of Exeter | University of Ferrara |
| University of Florida | University of Fribourg | University of Göttingen |
| University of Georgia | University of Gloucestershire | University of Guadalajara |
| University of Hanover | University of Helsinki | University of Illinois at Chicago |
| University of Illinois at Urbana–Champaign | University of Indonesia | University of Ingolstadt |
| University of Iowa | University of Jena | University of Jordan |
| University of Kansas | University of Lausanne | University of Leiden |
| University of Liverpool | University of Lyon | University of Manchester |
| University of Münster | University of Miami | University of Michigan |
| University of Montenegro Faculty of Biotechnology | University of Northern British Columbia | University of Oxford |
| University of Panama | University of Pennsylvania | University of Peshawar |
| University of Pittsburgh | University of Pittsburgh at Bradford | University of Queensland |
| University of Salamanca | University of Salford | University of São Paulo |
| University of Sheffield | University of St Andrews | University of Stanford |
| University of Stuttgart | University of Technology,Iraq-Baghdad | University of Texas at Austin |
| University of the Arts London | University of Toronto | University Of Tripoli Lebanon |
| University of tromso | University of Ulm | University of Washington |
| University of Waterloo | University of Wisconsin | University of York |
| University Park, Illinois | University Park, Iowa | University Park, Maryland |
| Unix | UNIX | Unix File System |
| Unix filesystem | Unix philosophy | Unix shell |
| UNIX System III | UNIX System V | Unix wars |
| Unix-Like | Unix-like | Unknown (2011 film) |
| Unknown Berlin Gospel | Unknown Soldier Memorial (Egypt) | Unladen Swallow |
| Unlicensed assistive personnel | Unmanned aerial vehicle | Unmanned combat aerial vehicle |
| Unmanned combat air vehicle | Unmanned ground vehicle | UNMIK Travel Document |
| Unnatural Causes: Is Inequality Making Us Sick? | Unnur Birna Vilhjálmsdóttir | Uno (card game) |
| Uno (dicycle) | Uno Cygnaeus | Unobtrusive JavaScript |
| UNODC | Unparser | UNPD |
| UNPO | Unpowered flight | Unreachable memory |
| Unreal 3 | Unreal Engine | Unreal Engine 3 |
| Unreal Tournament | Unrepresented Nations and Peoples Organization | Unrequited love |
| Unrestricted submarine warfare | Unsaturated fat | Unsaturated hydrocarbon |
| Unschooling | UNSMIL | Unstoppable (2010 film) |
| Unstructured data | UNStudio | Unsupervised learning |
| Untangle | Unter den Linden | Unterfranken |
| Unterfranken (region) | Unterhaltungssoftware Selbstkontrolle | Untermensch |
| Until Dawn | Untraceable | Ununennium |
| Ununhexium | Ununoctium | Ununpentium |
| Ununquadium | Ununseptium | Ununtrium |
| UNWTO | UO2 | UP |
| Up (2009 film) | UP (complexity) | Up antiquark |
| Up Close & Personal | Up in the Air (2009 film) | Up quark |
| Up2data | Up2date | Upalite |
| Upanishads | Upcycling | Upernavik Airport |
| Upgrade | Upham, North Dakota | Upham, Wisconsin |
| UPI | Upland, Nebraska | Uplands Park, Missouri |
| Upleward | UPnP | Upper alimentary tract |
| Upper Aulaqi Sheikhdom | Upper Austria | Upper Brookville, New York |
| Upper Cambrian | Upper class | Upper Devonian |
