Objectives To compare peer relationships among bereaved siblings and matched classmates, and to examine gender, grade level, and time since death as moderators. Methods Families were recruited from cancer registries at four hospitals 3–12 months after a child’s death. Measures of social behavior and peer acceptance were completed by children in the classrooms of 105 bereaved siblings (ages 8 –17 years). Teachers also reported on children’s social behavior. Three classmates were matched for gender, race, and age to each bereaved sibling to form a comparison group (n = 311). Results Teachers reported bereaved siblings were more prosocial than comparison classmates. Peers perceived bereaved boys as more sensitive-isolated and victimized, while bereaved siblings in elementary grades were perceived by peers as less prosocial, more sensitive-isolated, less accepted, and as having fewer friends. Peers and teachers viewed bereaved siblings in middle/high school grades as higher on leadership–popularity. Conclusions Bereaved siblings who were male and in elementary grades were more vulnerable to social difficulties, while those in middle/high school may exhibit some strengths. Ongoing research to inform the development of interventions for bereaved siblings is warranted.