Violence in childhood is a widespread human rights violation that crosses cultural, social and economic lines. Social norms, the shared perceptions about others that exist within social groups, are a critical driver that can either prevent or perpetuate violence in childhood. This review defines injunctive and descriptive social norms and lays out a conceptual framework for the relationship between social norms and violence in childhood, including the forces shaping social norms, the mechanisms through which these norms influence violence in childhood (e.g. fear of social sanctions, internalization of normative behavior), and the drivers and maintainers of norms related to violence in childhood. It further provides a review of theory and evidence-based practices for shifting these social norms including strategic approaches (targeting social norms directly, changing attitudes to shift social norms, and changing behavior to shift social norms), core principles (e.g. using public health frameworks), and intervention strategies (e.g. engaging bystanders, involving stakeholders, using combination prevention). As a key driver of violence in childhood, social norms should be an integral component of any comprehensive effort to mitigate this threat to human rights. Understanding how people's perceptions are shaped, propagated, and, ultimately, altered is crucial to preventing violence in childhood.