An aspect of the present disclosure provides a backlight unit with improved wrinkled phenomenon of optical sheet due to external factors such as temperature or humidity, and a display apparatus including the same. The display apparatus according to an embodiment includes: a backlight unit comprising an optical sheet; and an image forming unit configured to generate an image by transmitting or blocking light emitted from the backlight unit, and the optical sheet includes a plurality of sheets, and comprises a shape memory material in at least one of the plurality of sheets.