Polymer nanocarriers allow drug encapsulation leading to fragile molecule protection from early degradation/metabolization, increased solubility of poorly soluble drugs and improved plasmatic half-life. However, efficiently controlling the drug release from nanocarriers is still challenging. Thermoresponsive polymers exhibiting either a lower critical solution temperature (LCST) or an upper critical solution temperature (UCST) in aqueous medium may be the key to build spatially and temporally controlled drug delivery systems. In this review, we provide an overview of LCST and UCST polymers used as building blocks for thermoresponsive nanocarriers for biomedical applications. Recent nanocarriers based on thermoresponsive polymer exhibiting unprecedented features useful for biomedical applications are also discussed. While LCST nanocarriers have been studied for over two decades, UCST nanocarriers have recently emerged and already show great potential for effective thermoresponsive drug release.