Provided is a display device. The display device comprises a first substrate, wherein a first contact hole is defined in the first substrate, a barrier layer on the first substrate, wherein a second contact hole is defined in the barrier layer and connected to the first contact hole, a first connection line on the barrier layer and inserted into the second contact hole, a second substrate covering the first connection line and the barrier layer, and a thin-film transistor layer on the second substrate and including at least one thin-film transistor. The thin-film transistor layer further includes a second connection line connected between the first connection line and the at least one thin-film transistor.