Ensifera is a suborder of insects that includes the various types of crickets and their allies including: true crickets, camel crickets, bush crickets or katydids, grigs, weta and Cooloola monsters. This and the suborder Caelifera make up the order Orthoptera. Ensifera is believed to be a more ancient group than Caelifera, with its origins in the Carboniferous period, the split having occurred at the end of the Permian period. Unlike the Caelifera, the Ensifera contain numerous members that are partially carnivorous, feeding on other insects, as well as plants.

Crickets are orthopteran insects which are related to bush crickets, and, more distantly, to grasshoppers. In older literature, such as Imms, "crickets" were placed at the family level, but contemporary authorities including Otte now place them in the superfamily Grylloidea. The word has been used in combination to describe more distantly related taxa in the suborder Ensifera, such as king crickets and mole crickets.