AbstractSmartness in nature is inspiring for engineers to design biomimetic devices acting based on switchable properties. In this regard, nanomaterials able to show reversible optical properties have drawn immense attention from research and technology communities. Here, diverse classes of switchable plasmonic nanocomposites (SPNs) are introduced according to their stimuli, structure, and composition. The SPNs perform relying on reversible changes of the dielectric matrix' refractive index and physicochemical properties under the influence of various stimuli, leading to alteration in the interparticle spacing of the encapsulated plasmonic nanoparticles. The stimuli‐induced reversible reconfiguration of plasmonic nanoparticles, forming ordered or disordered structures, is considered another operation mechanism. The latter category involves a larger number of plasmonic nanoparticles and induces notable changes in optical properties by the switching process. Enhanced controllability over synthesis, function, and properties of the as‐developed metamaterials enables better scalability. Thus, SPNs hold great promise for next‐generation optical devices including optical switches, transducers, modulators, etc. As a specific highlight for the future perspective, the switchable plasmonic molecules‐based nanocomposites are introduced and recent progress is discussed. Ultimately, prospects, outlooks, and the current bottlenecks in this field are presented.