An organic light emitting display device includes: light emitting diodes respectively located in first to third sub-pixels on a substrate and respectively emitting red, green and blue color lights output upward through emission regions of the first to third sub-pixels; and a reflection structure located in a non-emission region surrounded by the first to third sub-pixels and including reflection side surfaces which are inclined and respectively face the emission regions of the first to third sub-pixels, wherein the reflection side surface reflects a light incident thereon from the corresponding emission region upward.