This chapter explores the current state of research on pure and modified SnO2 nanostructures related to their magnetic properties. Additionally, intrinsic properties of pure SnO2 nanostructures, defect-related properties, surface effects, and the effect of size and shape are discussed in detail. Modification of SnO2 through doping and surface modification is also studied with detailed discussions on transition metal doping (Co, Fe, Mn, Ni), non-metal doping (N, C) and the formation of magnetic nanocomposites. Additionally, the enhanced and tunable magnetic properties of modified SnO2 nanostructures by investigating the mechanism of ferromagnetism, the effect of dopant type and concentration with the magnetic behavior of nanocomposites were also comprehensively discussed. It also includes the effect of magnetic properties of SnO2 nanostructures in various applications such as data storage, spintronics, environmental remediation, and biomedical applications. Finally, the challenges and future directions were presented, addressing the current limitations, potential research avenues, and the commercialization potential of magnetic SnO2 nanostructures. Furthermore, the objective of this chapter is to gain a thorough understanding of the magnetic properties of SnO2 nanostructures. The chapter highlights the magnetic features of pure and modified SnO2 nanostructures in terms of their intrinsic property, dopant-induced effects, and application in fields such as gas sensors, catalysis, solar cells, optoelectronics, besides discussion of their commercial use.