Papaver rhoeas (common names include common poppy, corn poppy, corn rose, field poppy, Flanders poppy or red poppy) is an annual herbaceous species of flowering plant in the poppy family, Papaveraceae. This poppy is notable as an agricultural weed (hence the common names including "corn" and "field") and after World War I as a symbol of dead soldiers.

Before the advent of herbicides, P. rhoeas sometimes was so abundant in agricultural fields that it could be mistaken for a crop. However, the only species of Papaveraceae grown as a field crop on a large scale is Papaver somniferum, the opium poppy.