The Warnowiaceae are a family of athecate dinoflagellates (a diverse group of unicellular eukaryotes).

Studies of wild samples have found evidence of distinctive structures called trichocysts in warnowiid cell vacuoles, suggesting that their prey might be other dinoflagellates.

[3] Descriptions of genera and species within the family have been complicated by complex morphological changes during the life cycle and in response to the environment, and the systematics of this group is not currently well defined.

[1] Other complex subcellular structures, such as nematocysts, trichocysts, and pistons, are present in some (but not all) warnowiids and are shared with the polykrikoid dinoflagellates, the closest extant relatives as defined by molecular phylogenetics.

[5] A gene fragment that is expressed in the rhodopsin of the retinal body of the ocelloid has been shown to be most closely related to those of bacteria, suggesting a bacterial endosymbiont as the origin of the organelle.