An assembly for a drug delivery device is proposed, the assembly comprising: a housing (4); a clutch member (60); and a drive member (30), wherein one of the clutch member and the drive member is provided with at least one deflectable feature (67) and the other one of the clutch member and the drive member is provided with at least one interaction feature (35), the clutch member and the drive member are movable relative to one another between a first relative position and a second relative position, in the first relative position, the clutch member and/or the drive member is rotatable relative to the housing, in the second relative position, the deflectable feature is arranged to prevent rotation of the clutch member and/or of the drive member relative to the housing, and wherein the deflectable feature and the interaction feature are arranged such that, when the clutch member and the drive member are moved relative to one another from the first relative position into the second relative position, the deflectable feature and the interaction feature mechanically interact in order to deflect the deflectable feature.