The present invention relates to a housing for a drug delivery device, having a first housing component adapted to receive a cartridge at least partially filled with a medicament, and a second housing component adapted to receive a drive mechanism to operably engage with the cartridge for dispensing of a dose of the medicament, wherein the first housing component comprises an insert portion to be inserted in an axial direction into a corresponding receptacle of the second housing component, and wherein the insert portion comprises at least one radially outwardly extending first interlock member to positively engage and to rotationally lock with a correspondingly shaped second interlock member of the receptacle of the second housing component.
