AbstractPolymerization‐induced self‐assembly (PISA) is becoming a standard technique for generating core–shell polymeric nanoparticles of various morphologies ranging from classic spheres to rods/fibers (“worm‐like”) and vesicles. After the initial quest for polymerization control in dispersed media, the focus of PISA research has drastically shifted, first to morphological control and now to the introduction of reactivity and functionality in order to generate useful materials. The present review is dedicated to the latter aspect. Reactivity is distinguished from functionality such as complexing, templating, and catalyzing. Approaches for either shell or core functionalization are also detailed separately.