Recent technological advances in nanomaterials have driven the development of high-performance light-emitting devices with flexible and stretchable form factors. Deformability in such devices is mainly achieved by replacing the rigid materials in the device components with flexible nanomaterials and their assemblies (e.g., carbon nanotubes, silver nanowires, graphene, and quantum dots) or with intrinsically soft materials and their composites (e.g., polymers and elastomers). Downscaling the dimensions of the functional materials to the nanometer range dramatically decreases their flexural rigidity, and production of polymer/elastomer composites with functional nanomaterials provides light-emitting devices with flexibility and stretchability. Furthermore, monolithic integration of these light-emitting devices with deformable sensors furnishes the resulting display with various smart functions such as force/capacitive touch-based data input, personalized health monitoring, and interactive human-machine interfacing. These ultrathin, lightweight, and deformable smart optoelectronic devices have attracted widespread interest from materials scientists and device engineers. Here, a comprehensive review of recent progress concerning these flexible and stretchable smart displays is presented with a focus on materials development, fabrication techniques, and device designs. Brief overviews of an integrated system of advanced smart displays and cutting-edge wearable sensors are also presented, and, to conclude, a discussion of the future research outlook is given.