Thermoresponsive polymers constitute an important class of materials for biomedical application due to their thermally reversible coil-to-globule transition which can be exploited in a multitude of biomedical applications spanning from triggered drug delivery systems in the form of bulk hydrogels and nanoparticles, “smart” cell culture setups, sensors and actuators, and separation technologies. In this perspective article we present the basic physicochemical properties of poly (N-isopropylacrylamide) (PNIPAM), which is the most widely studied thermoresponsive polymer with a lower critical solution temperature. We describe the basic thermodynamic and physicochemical parameters that affect the LCST and present selective applications that utilize thermoresponsive polymers in the form of nano-assemblies including micelles, polymersomes, microcapsules and microgels, as well as injectable hydrogels for biomedical applications.