Peptoids, or poly(N-substituted glycine)s, hold great promise in biomedical applications because of their biocompatibility, precise synthesis via conventional peptide-mimicking methods, and readily tunable side chains, which facilitate the control of hydrophobicity and crystallinity. In the past decade, peptoids have been used to create well-defined self-assemblies such as vesicles, micelles, sheets, and tubes, which have been scrutinized at the atomic scale using cutting-edge analytical techniques. This review highlights recent advancements in peptoid synthesis strategies and the development of noteworthy one- or two-dimensional anisotropic self-assemblies, i. e., nanotubes and nanosheets, exhibiting well-ordered molecular arrangements. These anisotropic self-assemblies are formed through the crystallization of peptoid side chains, which can be effortlessly modified via simple synthesis approaches. Moreover, leveraging the protease resistance of peptoids, various biomedical applications are discussed (including phototherapy, enzymatic mimetics, bio-imaging, and biosensing) that capitalize on the unique properties of anisotropic self-assembly.