In this study, synthesis and characterization of semiconductor tin oxide (SnO2) thin films on glass substrate were systematically investigated by using sol-gel technique for gas sensing applications. Turbidity, pH values, wettability and rheological properties of solution were measured by turbidimeter, pH meter, contact angle goniometer and rheometer machines before coating process. The thermal, structural, microstructural and optical properties of the coatings and powders made from the sols were extensively characterized by using DTA-TG, FT-IR, XRD, SEM-EDS, refractometer and spectrophotometer. Four different solutions, including 6, 8, 10 and 14 mL methanol content, were prepared by sol-gel technique to determine solvent influence on microstructure and semiconducting properties of the thin films. Refractive indiceses, band gaps, absorbance and transmittance values of SnO2 thin films, containing different methanol quantity, were determined and their variations depending on solvent content were obtained. It is concluded that solvent content influences microstructural and semiconducting properties of Sn based oxide thin films notably.