A method of manufacturing an organic light-emitting device by using a solution process is provided. The method entails forming a first organic layer between a first electrode and a second electrode, and forming a second organic layer between the first organic layer and the second electrode. The forming of the first organic layer comprises performing a solution process using a composition comprising a first compound, a second compound, and a solvent. The forming of the second organic layer comprises depositing a third compound on the first organic layer. An absolute value of a difference between a relative polarity of the first compound and a relative polarity of the solvent is about 0.03 or less.