Carbon dots (CDots), an emerging class of photoluminescent materials, exhibit excellent optical, electrical and chemical properties with many potential applications. Hetero-atom doping in CDots represents a robust and versatile technique to further improve the chemical composition and structure properties of CDots. In this review, we provide an updated roadmap of the hetero-atom-doped CDots. Various up-to-date synthetic strategies, starting with different raw materials to synthetic methods to doping elements, are surveyed. Furthermore, the catalysis, optical properties, biological properties and the potential applications of hetero-atom doped CDots, including nano-probes, optoelectronic devices, catalysis, and biomedicine are also reviewed. We further provide an outlook towards future developments of the hetero-atom-doped CDots. This review will provide a summary of the latest progress of hetero-atom-doped CDots and is expected to inspire further developments in this exciting class of materials.