A display device includes: a first substrate comprising a display area including a plurality of pixels, and a peripheral area around the display area; a plurality of driving signal transmission lines on the first substrate and arranged in the peripheral area; a first insulating layer on the first substrate and arranged under the plurality of driving signal transmission lines; and a second insulating layer on a portion of the plurality of driving signal transmission lines and arranged in the display area, and the first insulating layer includes a trench between two driving signal transmission lines adjacent to each other among the plurality of driving signal transmission lines, and an edge portion of the second insulating layer overlaps the trench.