A light emitting device includes: a first substrate; a second substrate; a light emitting unit interposed between the first substrate and the second substrate; and a sealing material bonding the first substrate to the second substrate and sealing the light emitting unit. The sealing material comprises V+4. In addition, a glass frit, a composition for forming a sealing material, and a method of manufacturing a light emitting device using the composition for forming a sealing material are provided to obtain the light emitting device. The sealing material of the light emitting device can be easily formed by coating and irradiation of electro-magnetic waves, so that manufacturing costs are low and deterioration of the light emitting unit occurring when sealing material is formed can be substantially prevented. The sealing material has good sealing properties and thus a light emitting device including the sealing material has a long lifetime.