A dose setting mechanism (4； 200) for a drug delivery device is disclosed. The mechanism comprises an outer housing (40； 204) and an inner housing (208) having an external groove. The inner housing guides a driver (30； 209) to dispense a set dose. A dial sleeve (1 0； 206)is disposed between the outer and inner housing and is rotatably engaged with the inner housing. When a dose is set, the dial sleeve is rotated and translates away from both the outer housing and the inner housing.
