A bicycle rear derailleur is configured to be mounted to a bracket device formed separately from the bicycle rear derailleur. The bicycle rear derailleur includes a base element, a movable element, a linkage mechanism, and a chain guide. The base element includes a first base end and a second base end. The movable element is movably arranged relative to the base element. The linkage mechanism connects the movable element to the base element. The chain guide arrangement is rotatably connected to the movable element about a rotational axis. The second base end is coupled to the linkage mechanism. The first base end includes a first base arm and a second base arm. The first base end and the second base end are configured such that the derailleur attachment end is disposed between the first base arm and the second base arm in the mounting state.