An apparatus and method for displaying a three-dimensional (3D) image is disclosed. On a display panel, red, green and blue subpixels are alternately arranged in a row direction and subpixels having the same color are arranged in a column direction. A 3D image filter is disposed ahead of the display panel and includes a transparent area and a non-transparent area arranged alternately. An edge defining the width of the non-transparent area is inclined with respect to a vertical axis of the display panel. A controller assigns a view image to be displayed at a subpixel of the display panel according to an inclination angle of the edge.