| UCO | United Commercial Bank |
| UPSC | Union Public Service Commission |
| UNESCO | United Nations Educational, Scientific and Cultural Organization |
| UPA | United Production of America |
| UPA | United Progressive Alliance |
| UF | Ultra Filtration |
| UML | Unified Modeling Language |
| UPS | Uninterruptible Power Supply |
| UV | Ultraviolet |
| UTI | Urinary Tract Infection |
| USSR | Union of Soviet Socialist Republics |
| UNICEF | United Nations Children's Fund |
| UGC | University Grants Commission |
| URL | Uniform Resource Locator |
| USB | Universal Serial Bus |
| UPI | Unified Payment Interface |
| UPI | United Press International |
| UIDAI | Unique Identification Authority of India |
| USP | Unique Selling Proposition |
| UNDP | United Nations Development Programme |
| UDP | User Datagram Protocol |
| UNSC | United Nations Security Council |
| UNGA | United Nations General Assembly |
| UNO | United Nations Organization |
| UPTET | Uttar Pradesh Teacher Eligibility Test |
| UTET | Uttarakhand Teachers Eligibility Test |
| UPSC CSE | Union Public Service Commission Civil Service Examination |
| UPSC IAS | Union Public Service Commission Indian Administration Services |
| UPSC CDS | Union Public Service Commission Combined Defence Service |
| UPSC NDA | Union Public Service Commission National Defence Academy |
| UPSC IES | Union Public Service Commission Indian Engineering Services |
| UPSC CAPF | Union Public Service Commission Central Armed Police Forces |
| UPSC SCRA | Union Public Service Commission Special Class Railway Apprentice |
| UPPSC | Uttar Pradesh Public Service Commission |
| USET | Uttarakhand State Eligibility Test |
| URI | Upper Respiratory Infection |
| ULAST Time Zone | Ulaanbaatar Summer Time (Daylight Saving Time) |
| ULAT Time Zone | Ulaanbaatar Time (Standard Time) |
| UTC Time Zone | The World's Time Standard |
| UYST Time Zone | Uruguay Summer Time (Daylight Saving Time) |
| UYT Time Zone | Uruguay Time (Standard Time) |
| UZT Time Zone | Uzbekistan Time (Standard Time) |
