A series of thermoresponsive poly(γ‐propyl‐L‐glutamate)‐graft‐(oligo ethylene glycol)s (PPLG‐g‐OEGs) with different main‐chain and side‐chain lengths have been synthesized via copper‐mediated alkyne‐azide 1,3‐dipolar cycloaddition between poly(γ‐azidopropyl‐L‐glutamate)s (PAPLG) and propargyl terminated oligo ethylene glycols (Pr‐OEGs). Fourier transform infrared spectrometer analysis revealed that PAPLG10 adopted 39.4% β‐sheet, 47.4% α‐helix, and 13.2% random coil while PAPLG with longer main‐chain length (DP = 37 and 88) and PPLG‐g‐OEGs adopted exclusive α‐helix in the solid state. Circular dichroism analysis revealed that PPLG‐g‐OEGs adopted α‐helical conformations with helicities in the range of 50∼100%. The thermoresponsive behaviors of PPLG‐g‐OEGs in water have been studied by dynamic light scattering. The polymer concentration, main‐/side‐chain length, and helicity collectively affected their cloud point temperatures. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41022.