The present disclosure relates to a medicament delivery device. The medicament delivery device comprises a housing, a dispensing mechanism and an actuator. The housing has first and second portions. The dispensing mechanism comprises a reservoir disposed in the housing. The dispensing mechanism is operable to dispense medicament from the reservoir when the reservoir contains medicament. The first portion of the housing comprises a distal end and the second portion is moveable towards the distal end from an initial position to a primed position. The dispensing mechanism is rendered inoperable when the second portion is in the initial portion. The actuator is actuatable to operate the dispensing mechanism when the second portion is in the primed position.