Novel, well-defined, temperature- and/or pH-sensitive copolymer architectures were prepared by atom transfer radical (co)polymerization (ATRP) of a temperature-sensitive poly(methyl vinyl ether) (PMVE) macromonomer, obtained via living cationic polymerization of MVE initiated with inimer 3,3-diethoxypropyl acrylate. Temperature-sensitive comb architectures were obtained by ATRP homopolymerization (Me6TREN/ CuBr in toluene) of the PMVE macromonomer. ATRP copolymerization of the PMVE macromonomer with tert-butyl acrylate, a hydrolyzable precursor for pH-sensitive acrylic acid (AA), gives statistical graft copolymers. Palm-tree block copolymers containing a linear PtBA (PAA after hydrolysis) block and a branched block based on PMVE macromonomers were also prepared and fully characterized. Using turbidimetry, dynamic light scattering, FT-IR, and NMR, the temperature and/or pH responsiveness of those (co)polymer architectures are compared with the properties of previously synthesized linear block copolymers containing PMVE and PtBA or PAA.