The organic light-emitting display device includes: a substrate including a transistor region; and a thin-film transistor formed over the transistor region of the substrate and having a planarization film which is disposed over a source/drain electrode and a pixel defining layer which includes an aperture exposing a portion of a first electrode electrically connected to the source/drain electrode and defining a pixel region, wherein an outgassing hole is formed in a region of the pixel defining layer other than the aperture to expose the planarization film.