A display device includes a display substrate including at least one step portion, and a thin film encapsulation layer above the display substrate, the thin film encapsulation layer including a buffer layer configured to reduce a height difference due to the at least one step portion and a barrier layer above the buffer layer, the buffer layer including a plurality of sub-layers and interfaces between the plurality of sub-layers, and the interfaces including a curved surface changing from a concave shape to a convex shape toward a portion overlapping the step portion from an outer portion of the step portion.