We present here the results of selfconsistent field (SCF) and configuration interaction (CI) theoretical studies of seven low-lying electronic states of sulfur oxide. The basis set was of double zeta quality augmented with polarization functions. The CI space for each electronic state consisted of all configurations constructed from single and double substitutions of electrons from the valence orbitals of the Hartree-Fock reference occupation. Spectroscopic constants as well as dipole moments for each electronic state were predicted both at the SCF and CI levels of theory. Of particular significance is the prediction of excitation energies and properties for three low-lying states for which experimental information is either unavailable or only very recently available. These states are the c1∑- state (Te = 28 100±300 cm-1), the A′ 3Δ state (29 200±300 cm-1) and the A″ 3∑+ state (30 200±300 cm-1).