| Acronym | Definition |
|---|
| UU | Uppsala Universitet (University of Uppsala, Sweden) |
| UU | University of Ulster |
| UU | Unitarian Universalist |
| UU | University of Utah |
| UU | Undang-Undang (Malaysian tax) |
| UU | University of Utrecht (Netherlands) |
| UU | Unique User (Web metrics) |
| UU | United Utilities (UK) |
| UU | Uniqlo Undercover (clothing) |
| UU | Unix-To-Unix |
| UU | User-to-User |
| UU | Unter Umstaenden (German: Circumstances Permitting) |
| UU | Unix User |
| UU | Urbana University (Urbana, Ohio) |
| UU | Ureteroureterostomy (urology) |
| UU | Under Used (gaming) |
| UU | Unless Used |
| UU | Ultima Underworld |
| UU | Unconsolidated Undrained |
| UU | Until Uru (game) |
| UU | Utsunomiya University (Japan) |
| UU | Ultimate User |
| UU | User Unit |
| UU | Ultimate Use |
| UU | University of Uludag (Bursa, Turkey) |
| UU | Usmania University (India) |