In this study, the phase composition, surface morphology, and work function of molybdenum oxide (MoO₃) thin films deposited on siliconsubstratesby magnetron sputtering were comprehensively investigated. X-ray diffraction (XRD) analysis revealed that the films exhibited an amorphous structure. The film thickness was independently verified using two methods: a quartz crystal microbalance and reflectometry in the 2θ/θ geometry. Atomic force microscopy (AFM) demonstrated that the films formed a continuous coating over an area of 5×5 μm, with a surface roughness not exceeding 2 nm. Ultraviolet photoelectron spectroscopy (UPS) measurements showed that the work function was 5.8±0.2eV,remaining nearly unchanged for films with thicknesses of 10, 30, and150nm. Theobtained results indicate that amorphous, smooth MoO₃ films withahighworkfunction are promising as hole-injection layers in organic electronic devices.