Weeds are unwanted, harmful, or nuisance plant species in either wild or cultivated areas. Although many are non-natives, weeds may be either native or introduced plants, and they typically have fast-spreading, invasive characteristics with vigorous, rapid growth and aggressive reproduction and proliferation through seeds, roots, suckers, stem nodes, et cetera. Weeds are generally adaptable and remarkably tolerant of disturbed or damaged habitats, and they can quickly out-compete more desirable plant species.

State-listed noxious weeds are weeds that are prohibited, regulated and restricted in a particular state, while federal noxious weeds are those that are federally regulated.

Listed below are the Arizona State-listed Noxious Weeds and Federal Noxious Weeds profiled on this site.