Tin dioxide (SnO2) nanoparticles have gained significant interest in biomedical research because of their versatile applications across various clinical domains. SnO2 nanoparticles have been successfully implemented for a wide array of biomedical applications, involving antibacterial, antifungal, antioxidant, and anticancer applications. Although SnO2 nanoparticles possess great potential, their clinical application is limited because of the cytotoxicity. To tackle this challenge, the chapter offers insights into innovative breakthroughs to improve the biocompatibility of SnO2 nanoparticles in its drug delivery applications. Various organic as well as inorganic dopants are being introduced to SnO2 nanoparticles that contribute toward a reasonable enhancement in the physiological behavior of these nanoparticles without losing their in-vivo biocompatibility. Thus, these dopants play an important role in controlling the physicochemical characteristics of SnO2 nanoparticles which help to reduce cytotoxic effects and increase the therapeutic potential. This chapter examines how the biological activities of doped SnO2 nanoparticles are improved, discussing the interactions of SnO2 nanoparticles with biological systems, and possible mechanisms of action against microbial pathogens and cancer cells. In general, the crucial updates made in this chapter can serve as a useful resource for scientists and practitioners in nanomedicine for deploying the SnO2 nanoparticles’ advancements in the biomedical field. Employing a multidisciplinary strategy based on materials science- and engineered nanotechnological principles, through biology and medicine, this chapter highlights the relevance of the doped SnO2 nanoparticles as promising materials in future therapy strategies toward safer and more efficient biomedical approaches.