A display device is disclosed. In one aspect, the device includes a display panel including a display region and a non-display region and a housing accommodating the display panel therein. The device also includes a light sensing unit interposed between the display panel and the housing, the light sensing unit facing the display panel in the non-display region. The light sensing unit is configured to detect light that is totally reflected from the display panel and is emitted from a side of the display panel.