Polypeptoids, structural mimics of polypeptides, have attracted considerable attention due to their biocompatibility, proteolytic stability, thermal processability, good solubility, synthetic accessibility, and structural diversity. Polypeptoids have emerged as an interesting material in both polymer science and biological field. This review primarily discusses the research progress of polypeptoids prepared by controlled ring‐opening polymerizations in the past decade, including synthetic strategies of monomers, polymerizations by different initiators, postfunctionalization, fundamental properties, crystallization‐driven self‐assembly, and potential biological applications.