The research reported here provides an introduction to a theoretical model of socio-affective competence. This conceptual model of social effectiveness consists of four competencies that are related to the development of effective interpersonal relationships in the workplace. These competencies include: establishing rapport, promoting acceptance of differences, developing trust and cultivating charismatic influence. The socio-affective competence model was formulated in an attempt to integrate research on social and emotional skills that have been linked to performance in organizations. The current research proposed the model and defined its competency areas, designed a socio-affective competence situational judgment test (SAC-SJT), identified the variables that were theoretically related and unrelated to the construct, and provided initial evidence in support of the criterion-related validity of the socio-affective competence framework. Results from two different studies established the foundation of the socio-affective competence nomological network and demonstrated the predictive validity of the SAC-SJT on job performance, relational behaviors, and organizational citizenship performance. The author discusses the benefits of developing interpersonal relationship skills and the relevance of these findings in organizational settings.