A drive assembly for a drug delivery device, comprising a housing with a proximal end and a distal end, and a longitudinal axis (A) extending between the proximal end and the distal end, a rotation sleeve being rotatable relative to the housing, and a piston rod being axially moveable relative to the housing. The piston rod is in mechanical cooperation with the rotation sleeve to be rotatable and moveable in the distal direction relative to the housing when the rotation sleeve rotates in a first direction (D1) and to be stationary in axial direction relative to the housing when the rotation sleeve rotates in a second direction (D2) opposite to the first direction (D1).