A display device includes: a substrate comprising a first contact hole; a thin-film transistor layer on a first surface of the substrate and comprising a plurality of insulating layers and a thin-film transistor; an etching stopper on one or more of the insulating layers and contacting the substrate through a second contact hole surrounding the first contact hole in a plan view; a connection line on the etching stopper; and a pad part on a second surface of the substrate opposite the first surface of the substrate and connected to the connection line through the first contact hole.