ABSTRACT Transient electronics aim to align device lifetime with functional demand by enabling systems that physically dissolve or degrade after completing predefined tasks, thereby mitigating electronic waste and eliminating secondary surgical removal of temporary implants. Achieving this vision requires materials that couple electrical reliability and mechanical resilience with precisely programmable disappearance. Dynamic polymers, constructed from reversible dynamic interactions, provide a unifying strategy to meet these demands. By embedding bond reversibility at the molecular level, these networks enable continuous structural reconfiguration during operation, autonomous self‐healing, and stimulus‐triggered disassembly, transforming degradation from a passive consequence into an actively tunable function. This review outlines the fundamental chemistries of supramolecular and dynamic covalent polymer systems and analyzes how bond‐exchange kinetics govern electromechanical stability, interfacial integrity, and lifetime control in transient devices. We further discuss emerging applications in bioelectronic interfaces, flexible sensors, and energy storage platforms, highlighting the integration of adaptive mechanics with controlled degradation. Finally, we discuss key challenges, including biocompatibility, predictive lifetime programming, heterogeneous device integration, scalable manufacturing, and environmental closure. By positioning reversible chemistry as a central materials doctrine, dynamic polymers redefine transient electronics as adaptive systems capable of stable operation and programmed disappearance within a single molecular framework.