An assembly for a drug delivery device (1) comprises a housing (5), a rotation member (15), a drive member (16) and at least one correction member (7). The rotation member (15) is adapted to be rotated with respect to the housing (5) in a first rotational direction for delivering a dose of a drug (11). The drive member (16) is coupleable to the rotation member (15) for delivering the dose. In a delivery mode, the drive member (16) and the rotation member (15) are coupled such that the drive member (16) follows rotational movement of the rotation member (15) in the first rotational direction due to mechanical interaction of the rotation member (15) and the drive member (16). In a correction mode, the rotation member (15) and the drive member (16) are decoupled such that the rotation member (15) is rotatable in the first rotational direction with respect to the drive member (16). For switching from the delivery mode into the correction mode, the correction member (7) is moveable with respect to the housing (5), wherein the assembly is configured such that movement of the correction member (7) with respect to the housing (5) is converted into a relative movement between the drive member (16) and the rotation member (15) for decoupling the drive member (16) and the rotation member (15).