A method of manufacturing an organic light-emitting display device includes providing a substrate which comprises thin-film transistors (TFTs), and forming a planarization layer over the substrate. The planarization layer comprises a first planarization portion and a plurality of second planarization portions. The method further includes forming a plurality of first electrodes over the planarization layer, forming an organic light-emitting layer over each of the first electrodes, and forming a second electrode over the organic light-emitting layer. The forming of the planarization layer includes forming the first planarization portion which defines a plurality of first openings and forming one of the second planarization portions in each of the first openings.