Cadmium selenide (CdSe) quantum dots (QDs) have emerged as transformative nanomaterials in energy storage, leveraging their size-tunable electronic properties and high surface area to push the boundaries of batteries and supercapacitors. This review marks the first dedicated investigation of CdSe QDs specifically tailored for batteries and supercapacitors unraveling their potential to enhance charge storage, cycling stability, and electrochemical efficiency. We highlight cutting-edge advancements in integrating CdSe QDs into lithium-ion batteries, lithium-oxygen batteries, and supercapacitors, driven by innovative synthesis strategies and hybrid nanostructures. Key mechanisms, including pseudocapacitance and ion diffusion, are dissected to reveal how CdSe QDs elevate device performance. Despite cadmium toxicity challenges, breakthroughs in core-shell designs and surface passivation offer pathways to safer, high-performance systems. This work underscores CdSe QDs as pivotal players in next-generation electrochemical energy storage, bridging synthesis innovation with practical application.