The effect of the thickness‐dependent carrier concentration of degenerate tin‐oxide (SnO2) films on the optical parameters, e.g. refractive index (n), extinction coefficient (k), real part (ϵ′) and imaginary part (ϵ″) of the dielectric constant, are studied in the near‐infrared region. The dependence of the high‐frequency dielectric constant, the plasma frequency, and the conduction band effective mass on the carrier concentration is also studied and the results are compared with other papers on doped samples prepared by different methods.