The aim of this study was to analyse the interpersonal relationships in the school context of children living in different care settings (adoptive families, residential care centres, birth families). Participants were 76 children between eight and fourteen years of age (M = 10.78, SD = 1.38), belonging to one of three groups: international adoptees, children living in residential care in Spanish institutions, and a comparison sample of Spanish children living with their birth families with no connection with child protection. Sociometric information was collected in the classroom of each child during school hours. Internationally adopted children from Russia showed considerable difficulties in their relationships with peers; they were more likely to be rejected and their peers described them as less prosocial and somewhat more aggressive. With a better sociometric position than the adoptees, children in residential care were rated by their peers as more aggressive and less prosocial than the normative population. Coordination and integrated work between the family, protection centres, schools, and other social services should be a strategic priority in the promotion of healthy social development in these groups of children.