<p>Tin dioxide (SnO₂) has gained wide recognition as a potential candidate for high-capacity anode applications in sodium-ion battery systems due to its great advantages in theoretical capacity and costs. However, its practical application is hindered by several critical challenges, including substantial volume expansion during charge/discharge cycles, low electronic conductivity, and sluggish electrochemical reaction kinetics. In contrast, defect engineering offers a viable solution to these limitations. By strategically modifying crystal structures through oxygen vacancy creation, solid solution modification, and elemental doping, the sodium storage performance of SnO₂ anodes can be substantially improved. This review first provides a concise introduction to the challenges facing SnO₂ anodes and the limitations of conventional modification approaches. Subsequently, it systematically examines various approaches to boost the electrochemical behavior of SnO₂ as an anode material. Finally, the review outlines both the potential challenges and promising prospects of employing defect engineering to enhance the performance of SnO₂ as a high-efficiency anode material for sodium storage.</p>