Child abuse is a global problem that disrupts children's normal development and has several negative consequences, including poor school adjustment. Some researchers have shown that social support might help abuse victims adjust better to the school environment. Thus, this study investigates the moderator and mediator roles of perceived social support from parents, classmates, and teachers in the relationship between exposure to abuse and school adjustment. Data were collected within the study "Health Behavior in School-aged Children" (HBSC), conducted in Romania in 2014. The sample consisted of 1712 adolescents (M = 15.05 years, SD = 0.4), of which 55.4% girls and 44.6% boys. The results showed that abused adolescents, in some cases, perceive less parent, classmate, and teacher support and report lower school adjustment scores than non-abused ones. Exposure to abuse, single or multiple types, had a negative effect on school adjustment, while social support from the three sources had a positive effect. The three types of social support were both moderators and mediators of the relationship between exposure to some types of abuse and school adjustment. Findings have practical implications for abused children therapy and the design and implementation of prevention and intervention programs in schools.