A glass substrate has a first surface, a second surface opposite to the first surface, and a thickness from the first surface to the second surface. The glass substrate includes a first region, a second region, and a third region. The first region extends from the first surface a first depth into the glass substrate and has a first compressive stress. The second region extends from the second surface a second depth into the glass substrate and has a second compressive stress different from the first compressive stress. The third region is between the first region and the second region. In the glass substrate, the first compressive stress has a maximum value at a location between the first surface and the first depth, and the second compressive stress has a maximum value at a location between the second surface and the second depth.