An organic light-emitting device and a method of manufacturing the same. The organic light-emitting device includes a substrate, a first electrode formed on the substrate, a second electrode, an emission layer between the first electrode and the second electrode, a hole transport layer between the first electrode and the emission layer, and an electron transport layer between the second electrode and the emission layer. The hole transport layer includes a first hole transport unit comprising: a first hole transport layer comprising a hole transporting material, a third hole transport layer formed on the first hole transport layer and comprising a charge generating material; and a fifth hole transport layer formed on the third hole transport layer and comprising the hole transporting material.