A method of manufacturing a display device, the method including providing a first electrode on a base substrate; providing a fluorine-containing pixel defining layer on the base substrate and the first electrode such that the pixel defining layer exposes at least a portion of the first electrode; pretreating the first electrode; and providing an organic layer on the first electrode after pretreating the first electrode, wherein pretreating the first electrode includes performing a first treatment operation of treating an exposed surface of the first electrode using a first plasma gas; and performing a second treatment operation after performing the first treatment operation, the second treatment operation including treating the exposed surface of the first electrode using a second plasma gas, wherein the second plasma gas is different from the first plasma gas and includes hydrogen.