A method of manufacturing an organic light-emitting display apparatus includes forming a semiconductor layer on a substrate; forming a gate electrode on the semiconductor layer; forming an interlayer insulating film on an entire surface of the substrate to cover the gate electrode; forming a source electrode and a drain electrode on the interlayer insulating film; and forming a pixel electrode and a pixel-defining film on the source electrode and the drain electrode, wherein the forming of the pixel electrode and the pixel-defining film includes forming the pixel electrode and the pixel-defining film by using one mask.