Although parents’ health condition is generally thought to be related to their involvement in their children’s functioning, the possible dynamics behind the scenes in school contexts with immigrant children has received little attention. This study examined the association between parents’ health condition and their children’s academic and behavioral functioning, as well as the mediation effects of parents’ school engagement and children’s perceived treatment at school among 607 immigrant families with 10- to 12-year-old children. Using structural equation modeling, the results indicated that parents’ poor health condition was associated with children’s increased behavioral problems. Parents’ school engagement fully mediated the association between parental health condition and children’s academic achievement and partially mediated the association between parental health condition and children’s behavior problems. Notably, higher levels of parents’ school engagement were associated with increased behavior problems, demonstrating a unique feature in these immigrant children’s developmental functioning. Higher levels of perceived harsh treatment by peers at school due to children’s immigrant identity were associated with these children’s greater risks of behavior problems. The results suggested what may lie behind the scenes in these children’s behavioral problems is that many of these children who act out and are brought to the school office for disciplinary issues may suffer from perceived discrimination and bad treatment by their peers. The findings provide important implications for researchers, healthcare practitioners, and educators seeking to understand this subpopulation and to design and implement family support and prevention programs for young adolescents from immigrant backgrounds.