Background: The association of bullying victimisation by siblings with a) involvement in bullying at school and b) behaviour problems among lower secondary school children in Israel was investigated. Method: Self-report questionnaires of sibling victimisation, peer bullying experiences and behaviour problems were completed by 921 pupils aged 12-15 (mean age 13.7 years). Results: Of the sample, 16.2% were directly bullied by their siblings at home and 11.9% were direct victims of bullying by peers at school every week. More than half of victims of bullying by siblings (50.7%) were also involved in bullying behaviour at school compared to only 12.4% of those not victimised by siblings, indicating a strong link between intrafamilial and extrafamilial peer relationships. Children with poor sibling and peer relationships were at a highly increased risk for behaviour problems. Ethnic (Israeli Jewish vs. Arab) and sex differences were small compared to the effects of sibling relationship on behaviour problems. Conclusion: Intervention strategies directed at reducing bullying in school should take into account pupils' experiences of victimisation by siblings at home.