Many young children entering early childhood programs demonstrate challenging behaviors that place them at risk for emotional/behavioral disorders (EBDs), which impact their future success in school. The purpose of this study was to conduct a conceptual replication of BEST in CLASS by examining child outcomes from BEST in CLASS--Web, a web-based professional development intervention supporting teachers' use of effective practices for ameliorating young children's challenging behaviors. Participants included 29 early childhood teachers and 54 children (ages 3-5 years old) who were identified at-risk for EBD. Positive outcomes were found for both BEST in CLASS--Web and BEST in CLASS in reductions of children's problem behaviors and conflictual relationships with their teachers as well as increases in social skills, engagement, and closeness with teachers in comparison to children who did not receive the intervention. In some cases, positive child outcomes were greater when teachers received professional development in the web-condition as compared to the onsite condition. Future research directions and implications are discussed. [This is the online version of an article published in "Journal of Early Intervention." For the final published version of this article, see EJ1327318.]