The family includes about 2,625 species, grouped into 53 genera according to the database of the Royal Botanic Gardens, Kew and Christenhusz and Byng (2016).

Urticaceae species can be shrubs (e.g. Pilea), lianas, herbs (e.g. Urtica, Parietaria), or, rarely, trees (Dendrocnide, Cecropia).

Most disperse their pollen when the stamens are mature and their filaments straighten explosively, a peculiar and conspicuously specialised mechanism.

While the stings delivered by Urticaceae species are often unpleasant, they seldom pose any direct threat to health, and deaths directly attributed to stinging are exceedingly rare; species known to cause human fatalities include Dendrocnide cordata[4][5] and Urtica ferox.

[9] Modern molecular phylogenetics suggest the following relationships[10][11] (see also [12][13][14][15][16][17][18][19][20][21]): Moraceae (outgroup) Laportea Obetia Urera pro parte Touchardia Urera pro parte Poikilospermum Girardinia Dendrocnide Discocnide Nanocnide Urtica (including Hesperocnide) Procris Pellionia Elatostema Myriocarpa + Gyrotaenia Lecanthus Pilea (including Sarcopilea) Coussapoa Myrianthus Cecropia Leucosyke Maoutia Oreocnide Phenax Chamabainia Gonostegia Pouzolzia pro parte Neodistemon Rousselia Hemistylus Pouzolzia pro parte Neraudia Pipturus (including Nothocnide) Boehmeria pro parte Debregeasia Astrothalamus Archiboehmeria Boehmeria pro parte Sarcochlamys Forsskaolea Didymodoxa Droguetia (including Australina) Parietaria Soleirolia Gesnouinia The Urticaceae are subject to many bacterial, viral, fungal, and nematode parasitic diseases.