A backlight unit and a display device including the same are provided. The backlight unit includes a first substrate on which at least one transistor is disposed; a second substrate facing the first substrate; a heat dissipation sheet which is disposed on the second substrate and at least a part of which is in contact with the first substrate; and at least one light source disposed between the heat dissipation sheet and the first substrate and electrically connected to the transistor. The heat dissipation sheet includes a first region in contact with the first substrate and a second region separated from the first substrate, the second region being a region other than the first region.