A very simple sol-gel route to vanadium dioxide thin films is described. Vanadium alkoxide molecular precursors are deposited onto a fused silica substrate by the spin coating technique. An amorphous thin film is obtained at room temperature which leads to crystalline VO2 when heated at 450-degrees-C under a reducing atmosphere (Ar-H2). Sol-gel derived VO2 thin films have a good optical transparency. They exhibit a reversible semiconductor-metal transition around 70-degrees-C and their conductivity increases by three orders of magnitude when heated above that temperature.