|genus = Populus
|genus_authority = Carl Linnaeus|L.
|type_species = Populus tremula
|subdivision_ranks = Species
|subdivision = See text
Populus is a genus of 25–35 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English language|English names variously applied to different species include poplar (), aspen, and Populus sect. Aigeiros|cottonwood.
In the September 2006 issue of Science (journal)|Science, it was announced that the Western Balsam Poplar (Populus trichocarpa|P. trichocarpa) was the first tree to have its full DNA code DNA sequencing|sequenced.