A dry powder inhaler with a blister folding device can include a housing to receive a single blister containing a dose of medicament for inhalation by a user, and a mouthpiece through which a dose of medicament is inhaled by a user and a blister opening device. The blister opening device can include a blister support element for supporting a blister containing a dose of medicament for inhalation by a user, and a blister folding element co-operable with the blister support element. The blister folding element and the blister support element can be movable relative to each other between a first position, for insertion of the blister into or onto the blister support element, and a second, burst, position in which the blister folding element has co-operated with the blister support element.