This study investigated bullying among siblings in both traditional and cyber forms, and the associations of gender, grade, peer bullying perpetration, trait anger, and moral disengagement. The participants were 455 children in Grades 5 to 12 (262 girls and 177 boys with 16 unknown gender) who had a sibling. As the number of siblings who only bullied by technology was low, these associations were not able to be calculated. However, the findings showed that the percentage of sibling traditional bullying perpetration (31.6%) was higher than peer bullying perpetration (9.8%). Sibling bullies reported engaging in complex behaviors of perpetration and victimization in both the physical and in cyber settings, although the number was small. Gender, trait anger, moral disengagement, and bullying peers at school (but not grade) were all significantly associated with sibling traditional bullying perpetration. The implications of the findings are discussed for bullying intervention and prevention programs to understand childhood bullying in diverse contexts.