A series of pegylated polypeptoids have been readily synthesized by a strategy combining ring‐opening polymerization (ROP) and thiol‐yne photoaddition. The polypeptoids simultaneously incorporated branched oligo(ethylene glycol) (OEG) units and thioether bonds in the side‐chains. All the polypeptoids are readily soluble in aqueous solution and show reversible thermo‐responsive properties. The cloud points (CPs) were demonstrated to be readily tunable in the range of ~25 °C‐60 °C by varying the chemical composition, OEG chain length and the degree of polymerization. Attractively, the chemical compositions of the side chains are readily tunable via adjusting the molar ratios of a mixture of thiol terminated OEG molecules, which avoid synthesizing new monomers or copolymerization of different monomers. Further, the oxidation/reduction of thioether groups shows significant influence on the CPs, providing a second stimulus to tune the phase transition behaviors. Considering the biocompatibility and degradability, the dual‐responsive polypeptoids are potential candidates for various biomedical or biotechnological applications.