A method of manufacturing an organic light-emitting display apparatus includes: preparing a substrate including a display unit and peripheral parts; forming a cutting line on an encapsulation sheet to correspond to a boundary line between the display unit and the peripheral parts, wherein a size of the encapsulation sheet corresponds to that of the substrate; adhering the substrate and the encapsulation sheet together; removing the peripheral parts of the substrate; and cutting the encapsulation sheet along the cutting line. According to the method, a step height is not generated between the substrate and the encapsulation sheet when cutting the substrate and thus cracks may be avoided. Accordingly, products may be stably produced.