A display device includes a display module including a first non-folding area, a second non-folding area, and a folding area disposed between the first non-folding area and the second non-folding area and a support layer disposed under the display module. The support layer includes a first support plate, a second support plate disposed under the first support plate, and a spacer disposed between the first support plate and the second support plate. The spacer includes a main spacer and a sub-spacer alternately arranged with the main spacer in a first direction, the main spacer has a thickness greater than a thickness of the sub-spacer, and a length of the spacer in a second direction crossing the first direction is greater than a length of the first support plate in the second direction.