Summary: This study explores the synthesis and applications of SnO₂ nanoparticles, a key class of transition metal oxide semiconductors. With a band gap of 3.6-4.0 eV, SnO₂ nanoparticles exhibit high sensitivity, excellent thermal and chemical stability, rapid electron mobility, and superior electrical conductivity. These properties make them highly suitable for applications in transparent conductors, transistors, gas sensors, batteries, electrochromic devices, and photocatalysis. The review highlights various synthesis processes and their impact on material performance, particularly in energy and environmental sustainability.