UDF

UDF may refer to:

Astronomy

 * Ultra Deep Field, a view of the distant universe taken in 2004 by the Hubble space telescope
 * UDF 423, a distant spiral galaxy
 * UDF 2457, a red dwarf star

Computing

 * Universal Disk Format, an operating-system-independent file system commonly used on DVD and other digital media
 * Uniqueness Database File, a Windows XP Professional configuration text file
 * User-defined function, a function provided by the user of a program or environment

Politics

 * United Democratic Forces (ОДС), an electoral alliance in Bulgaria
 * United Democratic Forces of Belarus, a coalition of political parties participating as the main opposition group during the 2006 presidential election
 * United Democratic Front (Botswana)
 * United Democratic Front (Kerala), India
 * United Democratic Front (Mizoram), India
 * United Democratic Front (Malawi)
 * United Democratic Front (Namibia)
 * United Democratic Front (Pakistan)
 * United Democratic Front (South Africa)
 * United Democratic Front (South Sudan)
 * United Democratic Forum Party, a former political party in Kenya
 * Union pour la Démocratie Française (Union for French Democracy), a former centrist pro-European French political party

Military

 * Ulster Defence Force, a paramilitary group in Northern Ireland
 * Union Defence Force (South Africa), the predecessor of the South African Defence Force from 1912 to 1957
 * Union Defence Force (UAE), the armed forces of the United Arab Emirates

Other organizations

 * United Dairy Farmers, an American chain of ice cream shops

Other uses

 * Unducted fan, another name for a propfan engine
 * United Defense Force, a fictional global military in the manga All You Need Is Kill and its film adaptation Edge of Tomorrow
 * Ural Delay Factor, When your sidecar attracts attention from bystanders, thereby delaying your departure.