Amphiphilic miktoarm star copolymers have a unique internal structure and many attractive properties with respect to solution self-assembly, such as a high density of internal and peripheral functionalities, low CMC values, and high loading efficiency. However, compared to their linear analogs, the complex architecture demands asymmetric polymer arms emanating from a single core, which poses a significant synthetic challenge. Herein, we demonstrate an approach for the synthesis of polypept(o)ide-based AB3- and A3B-type miktoarm PeptoStars consisting of polypeptidic poly(γ-benzyl-l-glutamate (pGlu(OBn)) as the hydrophobic A arm and polypeptoidic polysarcosine (pSar) as the hydrophilic B arm. These structures, which are completely derived from endogenous amino acids, were realized by the core-first method using a tetrafunctional initiator and the corresponding N-carboxyanhydrides (NCAs) via a controlled, living nucleophilic ring-opening polymerization (ROP). The asymmetric architecture was achieved through an orthogonal protecting group strategy with multiple protection/deprotection steps. Characterization via 1H NMR-, 1H DOSY-spectroscopy, and size-exclusion chromatography (SEC) indicate the presence of well-formed miktoarm PeptoStars with low dispersities (Đ = 1.09–1.14), the precise control over the degree of polymerization and Poisson-like molecular weight distributions. Schwiertz et al. report on the synthesis of miktoarm star polymers based on polypept(o)ides by nucleophilic ring opening polymerization of N-carboxyanhydrides. The reported procedures allow for precise control over chain length, number of arms and end group functionality.