A method of displaying a three-dimensional (“3D”) image includes displaying a left-eye image and a right-eye image on a display panel, the display panel including a first sub pixel, a second sub pixel, a third sub pixel and a fourth sub pixel sequentially arranged in a row direction and driving an active barrier panel to form an opening part configured to transmit light and a barrier configured to block light, the active barrier panel including a first barrier electrode, a second barrier electrode, a third barrier electrode and a fourth barrier electrode respectively corresponding to the first, second, third and fourth sub pixels.