A bicycle derailleur comprises a base member, a movable member for supporting a chain guide, a first link member pivotably coupled to the base member and to the movable member through respective first and second link pins, a second link member pivotably coupled to the base member and to the movable member through respective third and fourth link pins, and a motor having a drive shaft that defines a drive shaft vector. The first through fourth link pins define edges of a phantom space, wherein straight continuous phantom lines connecting ends of the first through fourth link pins in a non-crossing manner define remaining edges of the phantom space. At least a part of the primary motor housing is disposed in the phantom space, and the drive shaft vector points away from a plane containing the second and fourth link pins.