Stereoscopic image display device and method for driving the same

The embodiments herein provide a stereoscopic image display device and method for driving the same capable of improving 2D image quality. The stereoscopic image display device comprises a display panel including a plurality of pixels; a 2D data converter configured to received two-dimensional data for each of a plurality of sub-pixels of the pixels and to convert the 2D data for each of the plurality of sub-pixels into converted 2D data for each of the plurality of sub-pixels based on all of the 2D data for the plurality of sub-pixels; and a display panel driving circuit configured to receive the converted 2D data for each of the plurality of sub-pixels and to supply each of the converted 2D data to a corresponding one of the plurality of sub-pixels in a two-dimensional mode of the stereoscopic image display device.