A method of manufacturing a display panel includes preparing a work substrate that includes a mother substrate that has a plurality of cell areas, a light emitting element layer formed in each of the cell areas, and an encapsulation layer formed on each cell area, disposing a plurality of protective films in the cell areas, respectively, that cover the light emitting element layer and the encapsulation layer, cutting the work substrate along cutting lines at an outer side of the protective films of each cell area to form a preliminary display panel, grinding side surfaces of the preliminary display panel, and removing the protective films from each ground preliminary display panel to form the display panel.