An organic light emitting diode (OLED) display device includes a substrate, reflection structure, and a sub-pixel structure. The substrate includes a plurality of sub-pixel regions and a reflection region surrounding the sub-pixel regions. The reflection structure is disposed on the substrate in the reflection region and has a plurality of openings exposing the sub-pixel regions. The reflection structure includes first reflection patterns, second reflection patterns, and connection patterns. The first reflection patterns extend in a first direction parallel to an upper surface of the substrate, and are spaced apart from each other in a second direction perpendicular to the first direction. The second reflection patterns are spaced apart from each other in the first direction between two adjacent first reflection patterns. The connection patterns electrically connect two adjacent second reflection patterns in the second direction. The sub-pixel structure is disposed on the substrate in the sub-pixel region.