This work, commissioned by the Office for Public Management of the UK government, was intended to conduct a review of existing literature in preventing violence (gun, gang activity) and violent extremism. The literature reviewed includes programs and interventions primarily in the UK, but also includes evidence from preveting violence and violent extremism in the US and broader Europe. The review collects good practices for addressing violence in a school setting, including the role of different actors (counselors, teachers) as well as curriculum development.