Child maltreatment has been an issue of concern worldwide. This study aims to explore the relationship between child maltreatment and children’s teacher-student relationships/peer relationships and the mechanisms of the relationship. Data were collected at two intervals of 12 months from 1,037 school-aged children (M = 9.57, SD = 0.65). This study divided child maltreatment into emotional and physical maltreatment. Both types of maltreatment were negatively associated with children’s teacher-student and peer relationships. After controlling for demographic variables, both cognitive reappraisal and expressive suppression fully mediated the effects of emotional maltreatment on both types of interpersonal relationships. In addition, expressive suppression also partially mediated between physical maltreatment and teacher-student relationships, and fully mediated between physical maltreatment and peer relationships. The current study provides an understanding of how different types of child maltreatment affect children’s relationships. This study also provides timely and necessary research to prevent and intervene in the harm that maltreatment causes to children.