UR, Ur or ur may refer to:

• Ur, also called Ur/Web a programming language.

Ur (Sumerian: Urim; Sumerian Cuneiform: or ; Akkadian: Uru; ) was an important Sumerian city-state in ancient Mesopotamia, located at the site of modern Tell el-Muqayyar in south Iraq's Dhi Qar Governorate. Although Ur was once a coastal city near the mouth of the Euphrates on the Persian Gulf, the coastline has shifted and the city is now well inland, south of the Euphrates on its right bank, 16 kilometres (9.9 mi) from Nasiriyah.

Úr is the Irish name of the eighteenth letter of the Ogham alphabet, , meaning "clay", "earth", "soil". In Old Irish, the letter name was also written Úir. Its phonetic value is [u] or [u:].

UR and A Tear in the Open are two electronic music tracks which appeared on Tiësto's second studio album in 2004, entitled Just Be. Unlike Tiesto's other album from 2004, Parade of the Athletes, Just Be featured only unmixed tracks.