Conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) has shown great potential for application in optoelectronic devices, sensors, and biomedicine. Flexible and stretchable PEDOT smart electronics have attracted great interest. Benefiting from the in-depth analysis of the structural properties of PEDOT and the development of fabrication techniques, many well-designed PEDOT composite membranes have been reported in the literature. In this paper, different structures of stretchable PEDOT membranes are reviewed, including wrinkled, cracked, fibrous, patterned, and micro–nano hierarchical structures. Top-down and bottom-up strategies for constructing stretchable PEDOT devices are reviewed, including blending, etching, deposition, templating, electrospinning/electrospraying, and various compositing methods. In addition, the applications of stretchable PEDOT membranes in smart electronics such as photovoltaics, light-emitting devices, organic thin-film transistors, sensors, thermal management, bioelectrodes, and wearable fabrics are reviewed. Future challenges for flexible and stretchable PEDOT membranes are proposed.