A viewing angle controllable display device and a driving method thereof. The viewing angle controllable display device includes: an image mixing unit generating a mixed image data signal by mixing an original image data signal, or a gray-adjusted original image data signal, with a protection image data signal that disturbs recognition of the original image; an output image selecting unit receiving the original image data signal or the mixed image data signal, and selecting an image data signal corresponding to an image output to a display panel; and a display panel receiving a data voltage corresponding to the image data signal selected and output from the output image selecting unit through a data drive to display an original image or a mixed image, responding to gate signals sequentially transmitted from a gate driver.