The Cattle Tyrant (Machetornis rixosa) is a species of bird in the Tyrannidae family. It is the only member of the genus Machetornis.

It is found in Argentina, Bolivia, Brazil, Colombia, Panama, Paraguay, Uruguay, and Venezuela. Its natural habitats are pastureland and heavily degraded former forest.

Cattle Tyrants feed on parasitic arthropods on mammals, an example of mutualism.