An organic light emitting diode (OLED) and a method of fabricating the same are provided. In the OLED, a second electron transport layer having an absolute value of a lowest unoccupied molecular orbital (LUMO) energy level smaller than that of a first electron transport layer is formed between a second electrode and the first electron transport layer, so that the second electron transport layer can suppress injection and transport of electrons under a low voltage condition to maintain a low current density. Accordingly, it is possible to prevent (or block) an element from emitting light when representing the color black. The OLED includes an emission layer on the first electrode, the first electron transport layer on the emission layer, the second electron transport layer on the first electron transport layer, and the second electrode on the second electron transport layer.