Tin dioxideTin dioxide (SnO2) is a very well-known n-type semiconductor material renowned for its superior thermalThermal stability, chemical inertness, and high band gap (~3.6 eV), which render it very suitable for a wide range of applicationsApplications such as gasSensors sensorsGas sensor, photocatalysis, transparent electrodes, and microelectronic devices. Aside from its traditional applicationsApplications, SnO2 is increasingly receiving attention based on its dielectricity, a characteristic highly beneficial to connect it to capacitive devices, memory, and sophisticated nanoelectronic devices. SnO2's dielectricity is not a material property in itself, however; it is highly dependent to an enormous degree on extrinsic influences like doping and the consequent microstructural change. Transition metal and rare-earth element doping in non-metals can affect the electronic structure, defect shape, and phase boundary nature of SnO2 nanoparticles, resulting in extreme modifications in polarization processes and dielectric properties. Modification of synthesis processes, crystallinity, particle dimensions, and surface shape also perform cardinal roles in controlling the dielectric properties of the material. This chapter strives to investigate the delicate interplay between dopant chemistry and microstructure in controlling dielectric behaviorDielectric Behavior of SnO2 nanoparticles. Elaborate discussions are delivered for different synthesis routes, strategic doping, and consequent structural and morphological developments. Dielectric characterization techniques are critically reviewed, providing insight into frequency and temperature dependent behavior, interfacial polarization, and defect-related contributions. By bridging the gap between fundamental materials science and practical device requirements, this chapter seeks to offer a holistic understanding of how rational design and engineering of SnO2 at the nanoscaleNanoscale can lead to enhanced dielectric functionality, paving the way for its applicationApplications in next-generation electronic and optoelectronicOptoelectronics technologies.