A drug delivery device (1) is provided comprising a housing (4), a lead screw (22) that is rotatably fixed with respect to the housing (4) during dose setting and during dose delivery and that is axially moveable in a delivery direction relative to the housing (4) for dose delivery, a number sleeve (23) threadedly engaged with the housing (4) to be screwable relative to the housing (4), and a dial link (25a) which is axially moveable and rotatable with respect to the housing (4) for dose setting and which is prevented from rotation with respect to the housing (4) for dose delivery. The dial link (25) is rotatably fixed with the number sleeve (23) when the dial link (25a) and the number sleeve (24) are in a first arrangement, and the number sleeve (24) and the dial link (25a) are rotatable with respect to one another when the dial link (25) and the number sleeve (24) are in a second arrangement. The device (1) further comprises a unidirectional coupling (100) which is adapted and arranged to allow a relative rotation between the dial link (25a) and the number sleeve (24) in a first direction while preventing relative rotation between the dial link (25a) and the number sleeve (24) in a direction opposite to the first direction when the dial link (25a) and the number sleeve (24) are in the second arrangement.
