| Acronym | Meaning |
| URI | Uniform Resource Indicator, URL |
| URL | Uniform Resource Locator, internet address |
| US | United States |
| USA | United States of America |
| USAF | United States Air Force |
| USB | Universal Serial Bus |
| USBM | United States Black Metal |
| USC | University of Southern California |
| USCG | United States Coast Guard |
| USD | United States Dollar |
| USMC | United States Marine Corps |
| USP | Unique Selling Point |
| USPS | United States Postal Service |
| USS | United States Ship |
| USSR | Union of Soviet Socialist Republics |
| USW | Und So Weiter (German for etc) |
| UT | Unreal Tournament |
| UTC | Coordinated Universal Time Under The Counter |
| UTD | Up To Date |
| UTE | Utility vehicle, pickup truck |
| UTF | Unicode Transformation Format |
| UTFL | Use The Force, Luke |
| UTH | Up The Hoods |
| UTI | Urinary Tract Infection |
| UTO | Unable To Obtain |
| UTP | Up-Town Projects |
| UTR | Under The Radar |
| UTS | Under The Skin |
| UTT | Under The Table |
| UV | Unpleasant Visual |
| UW | You’re Welcome |
| UWS | Upper West Side (of Manhattan) |
| UE | User Experience |
| UY | Up Yours |