Tin oxide (SnO2) is a versatile n-type semiconductor with a wide bandgap of 3.6 eV that varies as a function of its polymorph, i.e., rutile, cubic or orthorhombic. In this review, we survey the crystal and electronic structures, bandgap and defect states of SnO2. Subsequently, the significance of the defect states on the optical properties of SnO2is overviewed. Furthermore, we examine the influence of growth methods on the morphology and phase stabilization of SnO2for both thin-film deposition and nanoparticle synthesis. In general, thin-film growth techniques allow the stabilization of high-pressure SnO2phases via substrate-induced strain or doping. On the other hand, sol–gel synthesis allows precipitating rutile-SnO2nanostructures with high specific surfaces. These nanostructures display interesting electrochemical properties that are systematically examined in terms of their applicability to Li-ion battery anodes. Finally, the outlook provides the perspectives of SnO2as a candidate material for Li-ion batteries, while addressing its sustainability.