A beam deflector, a holographic display device including the beam deflector, and a method of driving the beam deflector are provided. The beam deflector includes first electrodes spaced apart from each other on a first substrate, second electrodes spaced apart from each other on a second substrate, a liquid crystal layer between the first substrate and the second substrate, and a controller configured to cause active prisms to be formed in the liquid crystal layer and to form a floating zone by turning off a voltage of at least one of the first electrode and the second electrode disposed between adjacent ones of the active prisms.