Hydrogel products are a group of polymeric materials that possess a hydrophilic structure, allowing them to retain significant amounts of water within their three-dimensional networks. The development of new materials is crucial for advancing technologies, and this often involves the innovative combination of existing components. A combination that incorporates both a polymer hydrogel network and nanoparticles can be achieved by combining metals, non-metals, metal oxides, and polymeric moieties. The composite material’s functionality will be enhanced by this amalgamation, which has applications in various fields such as catalysis, electronics, biosensing, drug delivery, nano-medicine, and environmental remediation. The incorporation of nanoparticles into hydrogels can result in synergistic property enhancements, such as improved mechanical strength of the hydrogel and a reduction in nanoparticle aggregation. These mutually beneficial effects have attracted significant interest from multidisciplinary research groups over the past decade. In this chapter, we delve into recent advancements in nanoparticle-hydrogel composites, focusing on their synthesis, design, potential applications, and the inherent challenges associated with these exciting materials.