Nanomonadea is a class of biciliate phagotrophic, non-photosynthetic free-living opalozoans, containing the sole order Uniciliatida.

[2][1] This monophyletic group previously known as clade MAST-3 is characterized by a single hairless posterior cilium and absence of an anterior cilium.

[1] The cladogram below shows the relationships between Nanomonadea and the rest of Opalozoans.

[1] Opalinea Blastocystea Opalomonadea Nanomonadea Placididea Pseudodendromonadida Bicoecida Anoecida Borokida Rictida The taxonomy of Nanomonadea is as follows:[1]