In Afghanistan, children are exposed to violence and a patriarchal society in which violence against women and children is normalised in everyday life. Little research has been conducted with children on the prevalence of violence-supportive attitudes, or the relationship between these attitudes and children’s experience of violence. As part of the What Works to Prevent Violence Against Women and Girls? Global Program, this paper aims to explore children’s violence-supportive attitudes and their relationship with experiences of violence in Afghanistan. A baseline survey was conducted to evaluate Help the Afghan Children’s peace education intervention, which aims to prevent violence perpetrated against and between children. Interviews were conducted with 770 children (420 girls and 350 boys) in 11 schools in Jowzjan Province. The survey tool included items that measure children’s violence-supportive attitudes, and experiences of peer violence and corporal punishment at home and at school. Violence-supportive attitudes among children in this study are prevalent, particularly among boys. Large proportions of children agreed with statements supporting violence against women, parental and teacher corporal punishment of children, and children’s violence against other children. Regression analysis found significant relationships between violence-supportive attitudes and experience of violence, particularly in relation to children’s perpetration of violence against other children. Children’s violence-supportive attitudes are strongly linked to their perpetration of violence against other children. Attitudes are learned and can be changed, and children’s violent behaviour can be prevented by changing social and cultural norms that support violence. Working with children to prevent violence against women and children is essential. However, in order to break the inter-generational cycle of violence, attitudinal change must take place among both children and adults.