Periodic arrays of nanoparticles (NPs) have garnered significant interest in the realm of nanodevice fabrication, owing to their distinctive photonic characteristics. A multitude of methodologies have been documented for the orchestrated assembly of nanoparticles into intricate superstructures, encompassing self-assembly, acoustic, optical, electrical, magnetic, and DNA ligation approaches. Among these, optical-based assembly techniques have emerged as a promising avenue, boasting the benefits of high resolution, adaptable manipulation, and the capacity to achieve arbitrary configurations of assembled structures. This chapter presents a comprehensive review of the recent advancements in the optical assembly of NPs and their associated applications. An in-depth discussion is provided on a variety of techniques predicated on disparate physical mechanisms, including optical force, photomechanical effects, optoelectronic interactions, photochemical reactions, laser-induced bubble formation, and photothermal effects. Given its versatility and adaptability, optical assembly technology is poised to have extensive application potential across numerous domains, including nanophotonics, energy, and nanomedicine.