A drug delivery device is provided, comprising: a housing (10), a movable member (60), which is arranged to be rotatable in two opposite rotational directions with respect to the housing, i.e. in an incrementing direction and a decrementing direction, the movable member being operatively coupled to an energy storage member (90) and biased to rotate into the decrementing direction by energy stored or storable in the energy storage member, wherein rotation of the movable member in the incrementing direction increases the energy stored in the energy storage member, a locking system, the locking system comprising a locking feature (62, 46, 160, 161), a block feature (42, 65, 66, 677), and a release member (70, 80), wherein the locking feature is arranged to cooperate with the block feature to form a releasable locking interface, the releasable locking interface being configured such that, when the releasable locking interface is established, rotational movement of the movable member relative to the housing is blocked in the decrementing direction, preferably only in the decrementing direction, and wherein, when the releasable locking interface is released, the movable member is rotatable in the decrementing direction, e.g. at least in a limited way, preferably only in a limited way or in a non-limited way, wherein the release member is rotatable relative to the housing and/or the locking feature at least in a limited way, preferably only in a limited way or in a non- limited way, between a first angular position and a second angular position, wherein, in the first angular position, the releasable locking interface is established, and, in the second angular position, the releasable locking interface is released at least temporarily, preferably only temporarily or permanently, where the assembly is configured such that the rotation of the release member from the first angular position to the second angular position causes the release of the releasable locking interface.La
