The magnetic and electronic properties of multiferroic TbMnO3 in the paramagnetic, antiferromagnetic, sinusoidal, and spiral-spin phases were studied by spectral generalized magneto-optical ellipsometry. The measurements show a strong anisotropy of the dielectric tensor. A redistribution of spectral weight was observed in the diagonal components of the dielectric tensor for the temperature range from 110 to =46K. In the off-diagonal elements, spectral generalized magneto-optical ellipsometry shows sensitivity to the antiferromagnetic and ferroelectric phase transitions at =46K and =29K, respectively, and a persistent signal up to 6.