A dry powder inhaler , comprising: a shell comprising an upper shell part and a lower shell part ; an inhalation piece through which a user can inhale medicament, wherein the inhalation piece is coupled to the lower shell part and wherein the upper shell part is moveable between a closed configuration in which it is coupled to the lower shell part and covers the inhalation piece , and an open configuration in which the inhalation piece is exposed; an actuation button coupled to the lower shell part and biased by a first biasing means acting between the actuation button and the lower shell part towards a projected position in which it projects from the surface of the lower shell part and moveable to a retracted position; wherein in use, movement of the actuation button from the projected position towards the retracted position causes medicament to be dispensed for subsequent inhalation through the inhalation piece ; wherein it further comprises a latch which when engaged retains the actuation button in the retracted position; wherein the latch comprises a latching projection that can be located over a corresponding latching edge so as to engage the latch , wherein the latching edge is the edge of a latching recess within which the latching projection is located when located over the latching edge ; wherein the upper shell part comprises the latching projection and the actuation button comprises the latching edge ; wherein, when the upper shell part is removed, the latch is disengaged as the latching projection is removed from the latching recess ; characterized in that , when the upper shell part is in the closed configuration, movement of the actuation button from the projected position to the retracted position cause the latching projection to locate over the latching edge and the latch to be engaged. a shell comprising an upper shell part and a lower shell part ; an inhalation piece through which a user can inhale medicament, wherein the inhalation piece is coupled to the lower shell part and wherein the upper shell part is moveable between a closed configuration in which it is coupled to the lower shell part and covers the inhalation piece , and an open configuration in which the inhalation piece is exposed; an actuation button coupled to the lower shell part and biased by a first biasing means acting between the actuation button and the lower shell part towards a projected position in which it projects from the surface of the lower shell part and moveable to a retracted position; wherein in use, movement of the actuation button from the projected position towards the retracted position causes medicament to be dispensed for subsequent inhalation through the inhalation piece ; wherein it further comprises a latch which when engaged retains the actuation button in the retracted position; wherein the latch comprises a latching projection that can be located over a corresponding latching edge so as to engage the latch , wherein the latching edge is the edge of a latching recess within which the latching projection is located when located over the latching edge ; wherein the upper shell part comprises the latching projection and the actuation button comprises the latching edge ; wherein, when the upper shell part is removed, the latch is disengaged as the latching projection is removed from the latching recess ; characterized in that , when the upper shell part is in the closed configuration, movement of the actuation button from the projected position to the retracted position cause the latching projection to locate over the latching edge and the latch to be engaged. <EOS>