| UG |
User Group, Underrun Goal |
| UGL |
Universal Glyph List |
| UHCI |
Universal Host Controller Interface |
| UHD |
User Help Desk |
| UHF |
Ultrahigh Frequency (300 MHz -- 3 GHz) |
| UHG |
Ultrahigh Gain (Antenna) |
| UHL |
User Header Label |
| UHN |
Unique Home Node |
| UI |
User Interface |
| UI |
UNIX International |
| UI |
Unnumbered Information (frame) |
| UIAP |
UNIX International Asia/Pacific |
| UIC |
User Identification Code |
| UID |
Unique/Unix/User Identifier |
| UIDL |
Unique Identifier Listing |
| UIFRAME |
Unnumbered Information Frame |
| UIL |
User Interface Language |
| UIM |
User Interface Management |
| UIML |
User Interface Markup Language |
| UIMS |
User Interface Management System |
| UIS |
User Interface Specification |
| UIT |
Union Internationale des Telecommunications |
| UKW |
Ultrakurzwelle |
| UL |
Upload |
| UL |
Underwriters Laboratory, Inc. |
| ULA |
Uncommitted Logic Array |
| ULD |
Unabhängiges Landeszentrum für Datenschutz, Kiel |
| ULN |
Universal Link Negotiation |
| ULP |
Unit in the Last Place |
| ULP |
Upper Layer Protocol |
| ULSI |
Ultra Large Scale Integration |
| ULSN |
Ultra Low Speed Networking |
| ULV |
Ultra Low Voltage |
| UM |
Unified Messaging |
| UMA |
Unified/Uniform Memory Access/Architecture |
| UMA |
Upper Memory Area |
| UMB |
Upper Memory Block |
| UMI |
User MAN Interface |
| UML |
User Mode Linux |
| UML |
Unified Modeling Language |
| UMM |
Unidirectional Multipoint to Multipoint |
| UMM |
Unix Macro Magician |
| UMS |
Unified Messaging System |
| UMTS |
Universal Mobile Telecommunications System |
| UN |
Unbalanced Normal |
| UN |
United Nations |
| UN/GTDI |
UN Guidelines for Trade Data Interchange |
| UNA |
Upstream Neighbour Address |
| UNC |
Unique/Universal Naming Convention |
| UNC |
Unbalanced Normal Class |