Backbone-thermoresponsive hyperbranched poly(propylene oxide)-based polyether polyols have been synthesized by anionic ring-opening copolymerization of glycidol and propylene oxide. The number of functional hydroxyl end groups and the lower critical solution temperature (LCST) can be readily adjusted by varying the comonomer ratio. Molecular weights in the range of 1200鈥?000 g/mol were achieved. Hyperbranched polyether polyols with LCST values between 24 and 83 掳C can be obtained in a convenient one-step reaction.