Molecular energy transfer in gas-phase collisions is of large interest in kinetics models. Vibrational excitation and deactivation processes can be concurrent with chemical reaction and/or sources of nascent excited species. In the present work, a full-dimension quasi-classical trajectory study of the vibrational deactivation of OH(v′ = 1,5) in collisions with SO is presented. A global potential energy surface for the ground electronic state of HSO₂, previously reported, is used to represent the interatomic interactions. The specific initial-state OH deactivation cross section and the corresponding SO activation cross sections are reported. Models for the maximum impact parameter and excitation function are discussed, while some details on the energy transfer mechanisms are also given. Specific initial-state deactivation thermal rate coefficients and vibrational average deactivation thermal rate coefficients are also presented and compared to previous results in the literature.