An organic light-emitting display apparatus includes a plurality of first emission units, each including a first organic light-emitting device configured to emit light in at least a first direction and through a first display surface, a plurality of second emission units, each including a second organic light-emitting device configured to emit in a second direction opposite to the first direction and through a second display surface. The first emission units and the second emission units are alternately disposed. The apparatus further includes a transmissive area disposed adjacent to but not overlapping with the plurality of first emission units and the plurality of second emission units when viewed from a direction perpendicular to the first display surface, and capable of transmitting external light through the first and second display surfaces in the transmissive area.