An organic light emitting display panel includes a first base substrate, a thin film transistor disposed on the first base substrate, a first electrode electrically connected to the thin film transistor, a pixel defining layer defining an opening that exposes a portion of the first electrode, a second electrode disposed on the first electrode, a light emitting structure disposed between the first electrode and the second electrode, a second base substrate disposed on the second electrode, and a first mirror layer disposed on the second base substrate and defining an opening that overlaps the light emitting structure. At least one of the pixel defining layer and the mirror layer has an uneven surface.