greenfly (plural greenflies or greenfly)
- Any of several kinds of common insects green in color:
- These bats prey on greenfly.
- Certain aphids (Aphidoidea), commonly known as greenfly in Britain and the Commonwealth
- Lucilia sericata, common green bottle fly
- Tabanus nigrovittatus, a biting horsefly more commonly known as the greenhead horsefly, greenhead fly, or greenhead
- Odontomyia chloris (syn. Musca chloris)