A quantum theory is developed for the interpretation of the Cotton-Mouton effect of paramagnetic complexes in solution. The results of this theory differ from those predicted by a classical analysis. The influence of ligand symmetry on the anisotropy in the orbital angular momentum is considered and anomalous dispersion is predicted in the vicinity of electronic absorption bands. Information concerning magnetic and optical anisotropies, the polarization of transition moments, and complex stereochemistries should emerge from experimental investigations.