A display device and a driving method thereof where different sounds are output depending upon characteristics of display images. The display device includes a display unit having a plurality of pixels, a signal controller, and a sound controller. The display unit displays images by selectively activating pixels from among the plurality of pixels in accordance with input video signals and input image control signals. The signal controller reads the input video signals to generate on-pixel signals having information about a ratio of a number of the activated pixels compared to a total number of pixels in the plurality of pixels per each frame and generating a sound output start signal. The sound controller determines a range from among predetermined ratio ranges corresponding to the ratio of the number of active pixels to define a plurality of volume levels, and determining the volume level corresponding to the on-pixel signal so as to generate a sound output instruction signal corresponding to the determined volume level.