The added value behind reversible bonds is the possibility to develop responsive structurally dynamic materials, which can adapt their constitution and, hence, properties to external stimuli. In recent years, much effort has been devoted to the design and synthesis of single‐chain polymer nanoparticles (SCNPs) that can be reversibly assembled or disassembled in response to external environmental changes or that can adapt even their structure through simple exchange reactions. Here, the evolution of the relatively new field of responsive SCNPs constructed via non‐covalent, or supramolecular, interactions, and “dynamic” covalent bonds is described in detail. The main reversible bonds commonly used in supramolecular polymer chemistry and dynamic covalent materials are summarized. A detailed description of the current reported routes to reversible unimolecular polymer nanoparticles is provided. Finally, future prospects of SCNPs constructed via supramolecular interactions and dynamic bonds are detailed.