Disclosed is an organic light emitting device including a first electrode, a second electrode opposite to the first electrode, and at least one organic layer interposed between the first and second electrodes. The organic layer includes first and second compounds represented by Formulae A and B, respectively: The organic light emitting device exhibits low driving voltage, high efficiency, and long life. Due to these advantages, the organic light emitting device is useful in a variety of industrial applications, including displays and lighting systems.