Recent advanced studies on flexible and stretchable electronic devices and optoelectronics have made possible a variety of soft and more functional electronic devices. With consumer demand for highly functional or free-form displays, high flexibility and stretchability in light-emitting devices are needed. Herein, we developed a unique structure of stretchable substrates with pillar arrays to reduce the stress on the active area of devices when strain is applied. We confirmed the advantages of the produced structures using mechanical simulation tools and determined that the structures effectively lessen the applied stress of interconnection as well as the active area in a stretched state. With this stress-relief stretchable substrate, we realized stretchable OLEDs that are compliant and maintain their performance under high strain deformation. Also, devices can be stretched in the biaxis, which is superior to only one-directional stretchable electronics; as such, devices can be used in practical applications like wearable electronics and health monitoring systems. We propose, for the first time, stretchable OLEDs patterned by the thermal evaporation fabrication process onto stress-relief substrates. These OLEDs can mitigate certain problems in previous studies of stretchable OLEDs without need to find new materials or to use a prestrained fabrication process.