Poplar River may refer to:
- Canada
- Manitoba
- Poplar River (Manitoba)
- Poplar River First Nation, a First Nation community astride the river in Manitoba
- Ontario
- Kenora District
- Poplar River (Atikameg River), part of the Kapiskau River system
- Poplar River (Fawn River), in the Severn River system
- Poplar River (Manitoba) (the upper reaches of which are in Ontario)
- Poplar River (Nipissing District), in Nipissing District, part of the French River system
- Poplar River (Montana–Saskatchewan), a tributary of the Missouri River in Saskatchewan in Canada and Montana in the United States
- United States
- Poplar River (Lake Superior), Minnesota
- Poplar River (Lost River), Minnesota
- Poplar River (Montana–Saskatchewan), a tributary of the Missouri River in Saskatchewan in Canada and Montana in the United States