AbstractWe report the diffuse light‐scattering properties of nanocracked and porous molybdenum trioxide (MoO3) films deposited on indium tin oxide (ITO) coated glass as a transparent conductive oxide (TCO), caused by the enhanced light diffraction due to high surface roughness as well as narrow slit‐like structures. By utilizing the electrodeposition and thermal annealing processes, the hydrous and amorphous molybdenum oxide films were changed into crystallized MoO3 films with self‐formed nanocracks and rough surface. From the theoretical analysis of the light behavior passing through the morphology of MoO3 films, a considerable diffuse light scattering was predicted. In order to optimize the light‐scattering property, the structural and optical characteristics of MoO3 films on ITO/glass at different applied voltages were investigated. For a proper applied voltage of 2 V, widely distributed nanocracks and rough surface were observed, leading to the enhanced diffuse transmittance of 54% at λ ∼ 410 nm. Additionally, the fabricated MoO3 films on ITO/glass exhibited a more hydrophilic surface.