This paper reviews the design and development of magnetothermally-triggered drug delivery systems, whereby magnetic nanoparticles are combined with thermally-activated materials. By combining superparamagnetic nanoparticles with lower critical solution temperature (LCST) polymers, an alternating current (AC) magnetic field can be used to trigger localized heating in vivo, which in turn causes a phase change in the host polymer to allow diffusion and release of drugs. The use of magnetic nanoparticles for biomedical applications is reviewed, as well as the design of thermally-activated polymeric systems. Current research on externally-triggered delivery is highlighted, with a focus on the design and challenges in developing magnetothermally-activated systems.