A light emitting device including a substrate, a first conductivity-type semiconductor layer, a mesa including a second conductivity-type semiconductor layer and an active layer, first and second contact electrodes respectively contacting the first and second conductivity-type semiconductor layers, a passivation layer covering the first and second contact electrodes, the mesa, and including first and second openings, and first and second bump electrodes electrically connected to the first and second contact electrodes through the first and second openings, respectively, in which the first and second bump electrodes are disposed on the mesa, the passivation layer is disposed between the first bump electrode and the second contact electrode, the first contact electrode includes a reflective material, and a portion of the first opening is surrounded with a side surface of the mesa, and another portion of the first opening is not surrounded with the side surface of the mesa.