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 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