UDP

 UDP  may refer to:

Political parties

 * Ulster Democratic Party, in Northern Ireland
 * União Democrática Popular (People's Democratic Union (Portugal))
 * Unidad Democrática y Popular (Democratic and Popular Union), a former Bolivian umbrella party
 * United Democratic Party (disambiguation), multiple organisations

Science and technology

 * Undecaprenyl phosphate, a bacterial cell membrane carrier lipid
 * Uridine diphosphate, an organic chemical
 * User Datagram Protocol, a network communications method
 * User Defined Primitive, a construct in Verilog
 * Usenet Death Penalty, a discussion group disciplinary response
 * Universality-diversity paradigm

Other uses

 * Unit Deployment Program, a military assignment system
 * Unitary development plan, a land use planning system
 * Universidad Diego Portales (Diego Portales University), in Chile