Provided is a method of manufacturing an organic light emitting device, the method including forming a lower electrode on a lower substrate, forming an organic layer on the lower electrode, forming a light extraction layer including an adhesion layer and nanoparticles on an upper substrate, forming an upper electrode on the light extraction layer, and coupling the lower substrate to the upper substrate so that the upper electrode contacts the organic layer. The forming of the light extraction layer includes providing an adhesive between a first sacrificial substrate and the upper substrate, curing the adhesive to form the adhesion layer to form the adhesion layer, and removing the first sacrificial substrate to expose the adhesion layer. The first sacrificial substrate and the upper substrate are coupled to each other by the adhesion layer.