A resettable drive assembly for a drug delivery device (1) is provided. The drive assembly comprises a drive unit (3) for driving a piston rod (5) in a dispense operation of the device (1). The drive unit (3) comprises a first drive member (35), a second drive member (37) and locking means preventing a relative rotational movement of the first (35) and the second drive member (37) during a dispense operation and allowing a relative rotational movement for enabling a resetting of the device (1). Moreover, a drug delivery device (1) comprising a resettable drive assembly is provided.