In Greek mythology, Stentor was a herald on the Greek side during the Trojan War. His name has given rise to the adjective "stentorian", meaning loud-voiced, for which he was famous. See the Iliad, V, 783.

In biology, Stentor is a genus of ciliate protozoa, representative of the heterotrichs. The body is generally trumpet-shaped, hence the association with the herald, with a ring of prominent membranelles around the anterior "bell" that sweep in food and aid in swimming. Stentor are common in freshwater lakes and streams, usually attached to algae and other detritus. Some reach several millimetres in length, making them among the largest single-celled organisms.