Multicomponent polymerizations (MCPs) have received widespread attention and are becoming a powerful tool for the synthesis of polymers. The Cu(ɪ)-catalyzed MCPs are a vibrant branch of multicomponent polymerizations, which inherit the various advantages of multicomponent reactions (MCRs) and click reactions. This chapter will focus on the development of Cu(ɪ)-catalyzed MCRs in polymer synthesis. Click reaction-mediated multicomponent polymerization has been applied for the synthesis of a library of linear, hyperbranched, core–shell-type, graft and dendronized polymers with high molecular weights and high yields, which show great potential for the construction of functional polymer materials.