A method of manufacturing a display panel assembly includes: preparing a mother substrate on which are defined first regions and dummy regions respectively between adjacent first regions; forming pixel driving lines and pixels connected to the pixel driving lines on each of the first regions in a same process at the same time as forming circuit connection lines on each of the dummy regions; connecting a driving element which drives the pixels to the circuit connection lines of the dummy regions; dividing the mother substrate to separate the first regions and the dummy regions from each other, each of the separated first regions defining a thin film transistor board of the display panel assembly, and each of the separated dummy regions defining a driving circuit board of the display panel assembly; and connecting the driving circuit board to the thin film transistor board.