The Enoplia are a subclass of nematodes in the class Enoplea.
Enoplians are characterized by amphids shaped like ovals, stirrups, or pouches. Their bodies are smooth, without rings or lines. The esophagus is cylindrical and glandular.
Lorenzen described two orders, Enoplida and Trefusiida, in the 1980s based on morphology. With the advent of phylogenetic analysis, a reorganisation has been necessary, moving the Triplonchida here to create three orders and expanding it. 
The orders are distinguished mainly by habitat type.