Unitarian Universalism, a religion

United Airlines

Uppsala Universitet in Sweden

University of Utah in the United States

Until URU, a computer game

University of Ulster in Northern Ireland

Union University in the United States

Unix-to-Unix, as in uuencode, a data transport encoding

University of Utrecht, alternatively known as Utrecht University, in the Netherlands

UUNET (Internet Service Provider commonly referred to as 'UU')

IATA code for Air Austral airline

The letter combination of uu

"uu", an old way of spelling the letter "w" in certain Germanic languages (e.g. the Merseburg Incantations spell the name of the god Woden as Uuôdan).

Unique users. May be counted as part of web analytics in determining the popularity of a website.

NYSE stock ticker symbol for United Utilities

The Ulster Unionist Party (also UUP), a political party in Northern Ireland

Union Underground, former American rock band

The Unseen University (in the fictional Discworld novels of Terry Pratchett)