A light-emitting device includes a first electrode; a second electrode facing the first electrode; m emission units between the first electrode and the second electrode; and m−1 charge-generating unit(s) between adjacent ones of the emission units, where m is a natural number of 2 or more. The emission units each include an emission layer. At least one of the charge-generating unit(s) includes an n-type charge-generating layer and a p-type charge-generating layer; and the n-type charge-generating layer includes a first material and a second material. The first material includes an organic electron transport compound; and the second material includes at least one selected from an alkali metal, an alkali metal alloy, an alkaline earth metal, an alkaline earth metal alloy, a lanthanide metal, and a lanthanide metal alloy. The light-emitting device may have improved hole and electron balance, a decreased driving voltage, and excellent efficiency and/or lifespan characteristics.