An organic light-emitting display apparatus comprising: at least two pixel electrodes (311, 312) that are disposed adjacent to each other along a first direction and spaced apart from each other; a plurality of first additional pixel electrodes disposed separate from the plurality of pixel electrodes (311, 312); a plurality of second additional pixel electrodes disposed separate from the plurality of pixel electrodes (311, 312) and from the plurality of first additional pixel electrodes, and a pixel-defining layer disposed on the pixel electrodes (311, 312) and covering a part of each pixel electrode (311, 312), wherein the pixel-defining layer comprises first openings that expose at least a center portion of the pixel electrode (311, 312) and at least a first edge of the pixel electrode (311, 312) in a direction toward the adjacent pixel electrode (311, 312), wherein the pixel-defining layer covers the plurality of first additional pixel electrodes except a center portion of the first additional pixel electrodes, the pixel-defining layer covering all edges of the first additional pixel electrodes, the pixel-defining layer covers the plurality of second additional pixel electrodes except a center portion of the second additional pixel electrodes, the pixel-defining layer covering all edges of the second additional pixel electrodes, the first additional pixel electrodes and the second additional pixel electrodes are alternately arranged along first rows extending in a first direction, characterized in that: the pixel electrodes (311, 312) are arranged along second rows extending in the first direction, and first rows and second rows are alternately arranged along a second direction perpendicular to the first direction. at least two pixel electrodes (311, 312) that are disposed adjacent to each other along a first direction and spaced apart from each other; a plurality of first additional pixel electrodes disposed separate from the plurality of pixel electrodes (311, 312); a plurality of second additional pixel electrodes disposed separate from the plurality of pixel electrodes (311, 312) and from the plurality of first additional pixel electrodes, and a pixel-defining layer disposed on the pixel electrodes (311, 312) and covering a part of each pixel electrode (311, 312), wherein the pixel-defining layer comprises first openings that expose at least a center portion of the pixel electrode (311, 312) and at least a first edge of the pixel electrode (311, 312) in a direction toward the adjacent pixel electrode (311, 312), wherein the pixel-defining layer covers the plurality of first additional pixel electrodes except a center portion of the first additional pixel electrodes, the pixel-defining layer covering all edges of the first additional pixel electrodes, the pixel-defining layer covers the plurality of second additional pixel electrodes except a center portion of the second additional pixel electrodes, the pixel-defining layer covering all edges of the second additional pixel electrodes, the first additional pixel electrodes and the second additional pixel electrodes are alternately arranged along first rows extending in a first direction, characterized in that: the pixel electrodes (311, 312) are arranged along second rows extending in the first direction, and first rows and second rows are alternately arranged along a second direction perpendicular to the first direction.