UD or ud may refer to:

Companies UD Trucks, a Japanese truck manufacturer United Devices, a commercial distributed computing company United Distillers, a whiskey holding company Unterrified Democrat, an American newspaper Upper Deck, a manufacturer of collectibles and trading cards Hex'Air (IATA airline designator UD), a French regional airline

Organizations Unificación Democrática, the Democratic Unification political party in Honduras Unión Democrática, a political party in Guatemala Unlock Democracy, a British political organization Utenriksdepartementet, the Norwegian Ministry of Foreign Affairs Utrikesdepartementet, the Swedish Ministry of Foreign Affairs

Schools U.S. University of Dallas, Texas University of Dayton, Ohio University of Delaware University of Dubuque, Iowa University of Detroit Mercy, a Catholic university in Michigan University of Detroit Jesuit High School and Academy, a Catholic secondary school in Michigan

Elsewhere University of Dammam, Saudi Arabia University of Dublin, Ireland University of Durham, U.K.

Other , an abbreviation of the Spanish personal pronoun Udonis Haslem, American basketball player nicknamed UD and Captain UD Ud (cuneiform), a sign in cuneiform writing Universal Dependencies, a project in analyzing syntax Unanimous decision, in combat sports Unlawful detainer, or eviction, in property law Urban Dictionary, a crowdsourced online slang dictionary Regional decentralization entity of Udine, a province in Italy whose postal abbreviation is "UD"

See also Oud (sometimes spelled as ud), a short-neck lute-type, pear-shaped, fretless stringed instrument