This study assessed the social adaptation of sexually abused children and tested whether children's emotion regulation competencies mediated the association between child sexual abuse (CSA) and two outcomes of the social domain (i.e. withdrawal and social difficulties). A group of 283 child victims of sexual abuse and a comparison group composed of 60 nonabused children was recruited. Teachers completed questionnaires assessing the children's emotion regulation competencies, withdrawal, and social difficulties exhibited in the school context. Results showed that sexually abused children displayed poorer emotion regulation skills and higher levels of both withdrawal and social difficulties relative to nonabused children. CSA was associated with social difficulties and withdrawn behavior through the mediation of emotion regulation competencies. Teachers and school psychologists should be assisted in identifying children at risk of social difficulties and emotional dysregulation and schools be encouraged to adopt a trauma-informed approach.