Research Findings: Children's (n = 980) social competence during prekindergarten was assessed as a function of their teachers' (n = 233) exposure to the Preschool Promoting Alternative Thinking Strategies (PATHS) curriculum and 2 levels of support through MyTeachingPartner, a Web-based approach to professional development. Children in classrooms that implemented PATHS had increased levels of teacher-reported social competence over the course of the year. There were no associations between the use of PATHS and reductions in teacher-reported social problems. The results also suggested that teachers who used the MyTeachingPartner website more often reported greater gains in children's social competence. Practice or Policy: These findings have implications for the development and dissemination of social-emotional learning curricula and the provision of effective implementation supports for teachers. Continued work on the best ways to integrate technology into the professional development of teachers, both in service and preservice, is likely to enhance the accessibility and quality of supports for teachers. (Contains 4 tables.)