In this study, SnOx films were synthesized via thermal oxidation of Sn films at various temperatures ranging from 300 °C to 500 °C. The impact of oxidation temperature on the structural, optical, and electronic properties of the SnOx films was investigated using SEM, EDX, optical absorption, and impedance spectroscopy techniques. It was found that the oxidation temperature has a significant impact on the SnOx resistance, which decreases as the temperature increases due to improved SnOx crystallinity and enhanced electron mobility. Furthermore, an increase in recombination resistance suggests an improvement in interface quality and reduced charge recombination processes. Finally, the impact of SnOx electron transport layer properties on the photovoltaic characteristics of organic solar cells was investigated. It was observed that OSCs based on SnOx ETL obtained at higher oxidation temperature reveal enhanced photovoltaic characteristics.