To enhance the electrochromism of vanadium oxide films used as a counter electrode of tungsten oxide (WO 3) films in electrochromic (EC) devices, VM (Pr, Nd, Sm, Dy) oxide films were synthesized by vacuum evaporation and annealed at 400 °C. The effects of 25% rare earth addition on electrochromism, structure and optical properties of the vanadium oxide films were investigated. By using cyclic voltammetry, it was found that all VM (Pr, Nd, Sm, Dy) oxide films heated at 400 °C for 30 min showed ten times better cycling stabilities in PC solution than vanadium oxide films. In situ UV–vis–NIR spectroelectrochemical measurements confirmed that all VM oxide films had higher transmittances than vanadium oxide film under the colored state in vis and NIR. Of the VM oxide films, VSm oxide film showed a very small coloration efficiency (CE; 0.6) in vis and NIR, and showed good ionic and electronic conduction, implying its potential application as a counter electrode in EC devices. From XRD results, the formation of orthovanadate SmVO 4 and DyVO 4 was testified in VSm and VDy oxide films, respectively. Moreover, a close relationship between the doping effects of M 3+ and its radius was found.