An organic light-emitting device includes: a first electrode; a second electrode facing the first electrode; an emission layer between the first electrode and the second electrode; and a hole transport region between the first electrode and the emission layer, wherein the hole transport region includes a hole transport layer and a hole injection layer between the first electrode and the hole transport layer, the hole injection layer includes a first compound and a charge-generation material, the hole transport layer includes a second compound and does not include a charge-generation material, and the first compound and the second compound are each independently selected from compounds represented by Formula 1: The organic light-emitting device according to embodiments of the present disclosure may have low driving voltage, high efficiency, high luminance, and long lifespan.