An organic light-emitting display device including an encapsulating layer covering a light-emitting element and an encapsulating substrate on the encapsulating layer is provided. The organic light-emitting display device may include metal particles which are dispersed on an outer surface of the encapsulating substrate having a high thermal conductivity, so that damage of the light-emitting element due to external impact may be prevented. And, the organic light-emitting display device may include a capping layer covering the metal particles, so that the surface roughness due to the metal particles may be reduced.