There is recognition that social media can benefit personal selling and sales management, especially in the B2B context. This research draws on interactional psychology theory to propose and test a model of usage of social media in sales, analyzing individual, organizational, and customer-related factors. We find that organizational competence and commitment with social media are key determinants of social media usage in sales, as well as individual commitment. Customer engagement with social media also predicts social media usage in sales, both directly and (mostly) through the individual and organizational factors analyzed, especially organizational competence and commitment. Finally, we find evidence of synergistic effects between individual competence and commitment, which is not found at the organizational level. We conduct multiple regression analysis of data obtained by surveying 220 sales executives in the United States.