UX can refer to several things:
- in genealogical records ux signifies wife of
- Unix, a computer operating system
- HP-UX, Hewlett-Packard's version of Unix
- DG/UX, Data General's version of Unix
- A/UX, Apple's version of Unix
- User experience
- Ux or ux, is a digraph in the Esperanto x-system orthography, representing the non-syllabic semivowel sound, primarily in the diphthongs aŭ and eŭ or the consonant (in foreign names, such as Ŭaŝingtono for "Washington"), normally spelled as Ŭ or ŭ in the Esperanto alphabet
- the IATA airline designator code for Air Europa
- United Express
- Sony Vaio UX Micro PC, a series of UMPCs from Sony
- les UX, a group of Parisians who secretly "improve" Paris in out-of-the-way places
- Uranium-X (symbol Ux), an old name for protactinium