A display device includes a display substrate including a display area and a pad region, a first pad portion including a plurality of first pad terminals, the plurality of first pad terminals being arranged in a first direction, and a printed circuit board (PCB) including a base film and a second pad portion. The second pad is electrically connected to the first pad portion. The second pad portion includes a plurality of second pad terminals electrically connected to the plurality of first pad terminals, and a plurality of first test lines. The plurality of second pad terminals includes a plurality of sub-pad terminals. One of the plurality of first lines is connected to a first sub-pad terminal of the plurality of sub-pad terminals, and a second sub-pad terminal of the plurality of sub-pad terminals is not connected to any of the plurality of first lines.