An organic light-emitting device may include a substrate; an anode on the substrate; a hole transport region on the anode; an emission layer on the hole transport region; an electron transport region on the emission layer; and a cathode on the electron transport region. The electron transport region may include an electron injection layer including a first component which is a salt chloride and a second component which is at least one metal selected from ytterbium (Yb), scandium (Sc), vanadium (V), yttrium (Y), indium (In), cerium (Ce), samarium (Sm), europium (Eu), and terbium (Tb). In addition, the cathode may contacts the electron injection layer and may include an alloy of a first cathode metal including at least one of Ag, Au, Pt, Cu, Mn, Ti, Co, Ni, and W, and a second cathode metal including least one of Yb, Sc, V, Y, In, Ce, Sm, Eu, and Tb.