- UAX-19 (Unicode Standard AnneX 19, UTF-32 ( Superceded by Unicode Standard Version 4.0))
- UAX-2 (Unicode Standard AnneX 2, Sinhala, Tibetan, Mongolian ( Superceded by Unicode Standard Version 3.0))
- UAX-27 (Unicode Standard AnneX 27, UNICODE 3.1)
- UAX-3 (Unicode Standard AnneX 3, Exploratory Proposals for Less Common Scripts ( Superceded by Unicode Standard Version 3.1))
- UAX-6 (Unicode Standard AnneX 6, Standard Compression Scheme for Unicode)
- UAX-7 (Unicode Standard AnneX 7, Plane 14 Characters for Language Tags ( Superceded by Unicode Standard Version 4.0))
- UAX-8 (Unicode Standard AnneX 8, Unicode Standard Version 2.1 ( Superceded by Unicode Standard Version 4.0))
- UAX-9 (Unicode standard AnneX 9)
- UAZ (Ultrasonically Assisted Z-fiber insertion)
- UB (Uniform Bill)
- UB-04 (Uniform Billing Form, modified in 2004)
- UB1 (Universal Barrel mount Type 1)
- UB-1 (University weekly-produced hourly report)
- UB-2 (University Bi-weekly-produced hourly report)
- UB5 (Umpire Brush model 5)
- UB-92 (Uniform Billing Form, modified in 1992)
- UBA (Mário de Almeida Franco Airport)
- UBACS (Under Body Armour Combat Shirt)
- UBB (Ultimate Bat Bag)
- UBC (Used Beverage Container)
- UBD (User Brain Damage)
- UBE (Upper Band Edge)
- UBEC (Universal Basic Education Commission (Nigeria))
- UBER (Universal Binding Energy Relation)
- UBF (United By Fate)
- UBFA (United Black Fund, Inc., of America)