Vanadium oxide (VOx) thin films were synthesized using DC magnetron sputtering with a vanadium target prepared by spark plasma sintering (SPS) at 900 °C under Ar+H2 atmosphere. Amorphous VOx films were deposited on glass substrates and annealed in air and oxygen atmospheres at 200–500 °C to study crystallization and surface properties. XRD analysis revealed phase separation into V2O5 and VO2 at 400 °C, with oxygen annealing enhancing VO2monoclinic phase formation, critical for thermochromic applications. AFM and SEM-EDX showed that higher annealing temperatures increased surface roughness and oxygen content, with oxygen-treated films exhibiting smoother morphology. The results demonstrate the influence of annealing conditions on the structural and morphological properties of VOx thin films for optoelectronic applications.