The Oxymonads (or Oxymonadida) are a group of flagellated protists found exclusively in the intestines of animals, mostly termites and other wood-eating insects.

Along with the similar parabasalid flagellates, they harbor the symbiotic bacteria that are responsible for breaking down cellulose.

[6][7] They lack aerobic mitochondria and have four flagella separated by a preaxostyle, but unlike the oxymonads have a feeding groove.

This character places the Oxymonads, Trimastix, and Paratrimastix among the Excavata, and in particular they may belong to the metamonads.

Molecular phylogenetic studies indeed place Preaxostyla (oxymonads, Trimastix, and Paratrimastix) in Metamonada.