The present disclosure is generally directed to a drug delivery device for selecting and dispensing a number of user variable doses of a medicament and to a housing for such a device. The housing comprises an outer housing with a distal end and a cartridge holder with a proximal end, which, when the cartridge holder is attached to the outer housing, is inserted into the distal end of the outer housing. The outer housing is provided with a first fixture for axially constraining a further component part to the outer housing. When the cartridge holder is attached to the outer housing, the proximal end of the cartridge holder axially extends to the first fixture.