A window includes a tempered glass substrate that includes a base layer and a compressive stress layer including a first region and a second region. The second region includes a first portion that includes a first point and is adjacent to the first region, a second portion that includes a second point and is adjacent to the base layer, and a third portion that includes a third point and that is disposed between the first portion and the second portion. A compressive stress at the first point is in a range of about 100 MPa to about 250 MPa, a compressive stress at the second point is in a range of about 50 MPa to about 150 MPa, and a compressive stress at the third point is in a range of about 70 MPa to about 200 MPa.