An organic light emitting device includes a first electrode for providing holes, a second electrode facing the first electrode and providing electrons, an organic luminescent layer interposed between the first and second electrodes, and an electron transfer layer disposed between the second electrode and the organic luminescent layer, wherein the electron transfer layer is a single layer including electron transfer members so that the electron transfer layer injects and transports electrons to the organic luminescent layer while preventing holes from the first electrode from flowing into the electron transfer layer.