Abstract: An organic light-emitting diode including a first electrode; a second electrode facing the first electrode; an emission layer interposed between the first electrode and the second electrode; a first hole transport layer including a first hole transporting compound; a second hole transport layer including a second hole transporting compound, the first and second hole transport layers being interposed between the first electrode and the emission layer; an electron transport layer interposed between the emission layer and the second electrode; a first mixing layer interposed between the first electrode and the first hole transport layer, contacting the first hole transport layer, and including the first hole transporting compound and a first cyano group-containing compound; and a second mixing layer interposed between the first electrode and the second hole transport layer, contacting the second hole transport layer, and including the second hole transporting compound and a second cyano group-containing compound