 Recent advances in plasmonic nanoparticles have led to exciting developments in energy, catalyst chemistry, optics, biotechnology, and medicine with a focus on photothermal therapy, sensing, imaging, therapy, and drug delivery. The future directions of these fields include better understanding and controlling the fundamental properties of photothermal nanoparticles and exploring their potential for clinical and other applications. This article was authored by Miho Kim, Younghoon Lee, and Jwamin Nam.