The electronic and magneto-optical properties of Pr monopnictides have been studied from the self-consistent electronic structure calculation employing full potential linear muffin-tin orbital method. The local spin density approximation along with on site Coulomb interaction (LDA+U) is used for electronic structure calculation. The inclusion of U in LDA results in low density of states at the Fermi level which imply that Pr monopnictides are semimetals. The spin and orbital magnetic moments primarily arise from the f states. The Kerr spectra are significant with sharp and large rotation of -5° at the lower energy region. The occupied f states are approximately 4 eV below Fermi level and do not contribute directly to optical transitions in the interested range of energy. These investigations suggest that the plasma frequency and the orbital magnetic moment play key roles for determining the magneto-optical spectra.