An organic light-emitting device includes a first electrode, a first light-emitting layer, a first low work function layer, a second low work function layer, a conductive etching-resistant layer, a first hole-injection layer, a second light-emitting layer, and a second electrode. The first light-emitting layer is disposed over the first electrode. The first low work function layer is disposed over the first light-emitting layer. The second low work function layer is disposed over the first low work function layer, and a work function of the second low work function layer is greater than a work function of the first low work function layer. The conductive etching-resistant layer is disposed over the second low work function layer. The first hole-injection layer is disposed over the conductive etching-resistant layer. The second light-emitting layer is disposed over the first hole-injection layer. The second electrode is disposed over the second light-emitting layer.