An organic light-emitting display apparatus includes: a substrate, and an organic light-emitting device disposed on the substrate. The organic light-emitting device includes a first electrode, a second electrode, and an intermediate layer including at least an organic emission layer. In addition, the organic light-emitting display apparatus further includes a thin film encapsulating layer disposed on the organic light-emitting device. The thin film encapsulating layer includes at least one inorganic film including a low temperature viscosity transition (LVT) inorganic material. The LVT inorganic material includes tin oxide and at least one of boron oxide (B2O3), bismuth oxide (Bi2O3), barium oxide (BaO), and ammonium dihydrogen phosphate (NH4H2PO4).