A nasal delivery device for and method of delivering substance to a nasal airway of a subject, the delivery device comprising: a nosepiece for fitting to a nostril of a subject a delivery unit comprising a substance supply unit and a nozzle unit including at least one nozzle fluidly connected to the substance supply unit for generating an aerosol spray for delivery to a nasal airway of the subject and an aerosol interactor operable to interact with an aerosol spray as generated by the at least one nozzle.
