Disclosed herein are an organic light-emitting diode and an organic light-emitting display device including the same. The organic light-emitting diode includes: a first electrode; a first light emitting structure disposed on the first electrode and including a first organic emissive layer; a second light emitting structure disposed on the first light emitting structure and including a second organic emissive layer; a third light emitting structure disposed on the second light emitting structure and including a third organic emissive layer; and a second electrode on the third light emitting structure, wherein a full width at half maximum (FWHM) of a peak wavelength of light emitted from each of the first organic emissive layer and the third organic emissive layer is within a range from 26 nm to 36 nm, inclusive.