An organic light-emitting display apparatus and a manufacturing method thereof. The organic light-emitting display apparatus includes a substrate, a display unit arranged on the substrate, a dam unit arranged at a periphery of the display unit and on the substrate and an encapsulating layer to encapsulate the display unit, wherein the encapsulating layer includes an organic film covering the display unit, and an inorganic film covering the organic film and the dam unit, and wherein a hardness of the dam unit is lower than that of the inorganic film. According to this, lateral moisture-proof characteristics of the organic light-emitting display apparatus are improved.