An organic light emitting display is formed with a plurality of display panels that are cut and separated from a mother substrate to form a unit display panel. Here, the substrate has a groove on its outer surface to improve the deformation strength of the cutting surface and to protect the strength of the panel from being degraded by improving the quality of the cutting cross-section. The organic light emitting display includes: a first substrate formed with a plurality of display panels partitioned by a cutting line and having a first groove on its outer surface corresponding to the cutting line; and a second substrate overlapped with an upper part of the first substrate and having a second groove on its outer surface corresponding to the cutting line, wherein the first and second grooves are formed with cutting positions lower than that of the outer surfaces of the respective substrates.