An organic light emitting device includes a first electrode; a second electrode; an emitting layer interposed between the first electrode and the second electrode; and a hole injection layer interposed between the first electrode and the second electrode. The hole injection layer includes a first compound having an element selected from the group consisting of Mo, Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, and B and an element selected from the group consisting of O, F, S, Cl, Se, Br, and I; and a second compound that is an organic hole injection layer forming compound. These compounds have excellent electrical properties, and are suitable for a fluorescent and phosphorescent device emitting light of a full range of colors, such as red, green, blue, or white. Therefore, an organic light emitting device including the hole injection layer exhibits a high efficiency and high luminance at low voltage, and has a long lifetime.