An organic light-emitting display apparatus includes: a thin film transistor including an active layer, a gate electrode, a source electrode, a drain electrode, a first insulating layer, and a second insulating layer; a pad electrode comprising a first pad layer and a second pad layer on the first pad layer; a third insulating layer covering the source electrode and the drain electrode and an end portion of the pad electrode; a pixel electrode comprising a semi-transmissive electrically conductive layer at an opening in the third insulating layer; a protection layer between the pixel electrode and the first insulating layer; a fourth insulating layer having an opening at a location corresponding to the opening formed in the third insulating layer and covering the end portion of the pad electrode; an emission layer on the pixel electrode; and an opposing electrode on the emission layer.