A nasal delivery device for delivering particulate substance to the nasal airway of a subject, the delivery device comprising: a mouthpiece unit (109) which includes a mouthpiece (147) through which the subject in use exhales； a nosepiece unit (105) which includes a nosepiece (141) for fitting to a nostril of the subject； and a substance-supply unit (111) which is configured to receive a container (C) containing particulate substance and operable to provide a metered amount of substance in fluid communication with the mouthpiece and nosepiece units (109, 105), such that an exhalation air flow delivered through the substance-supply unit (111) entrains the substance； wherein the container (C) comprises first and second parts (115, 117) which together define an enclosed chamber (119) and are movable between a first, closed configuration in which the container (C) is closed and a second, open configuration in which the container (C) is open, and the substance-supply unit (111) is operable to move the first and second parts (115, 117) of the container (C) to the open configuration.
