The report builds on a workshop held in April 2014, which was attended by experts in communication technology, criminology, developmental and clinical psychology, education, mental health, neurobiological development, pediatrics, public health, school administration, school-district policy, and State law and policy. This report is based on an extensive review of relevant literature, supplemented by findings from two public information sessions and a site visit to a northeastern city. The report uses the following definition of “bullying” adopted by the Centers for Disease Control and Prevention (CDC): “Bullying is any unwanted aggressive behavior(s) by another youth or group of youths who are not siblings or current dating partners that involves an observed or perceived power imbalance and is repeated multiple times or is highly likely to be repeated.” The definition also includes the statement that “Bullying may inflict harm or distress on the targeted youth, including physical, psychological, social, or educational harm.” Regarding cyber bullying, the report concludes that significant short- and long-term internalizing and externalizing psychological consequences result for both the victims and the perpetrators. Regarding the risk ad protective factors for bullying, the report concludes that contextual factors operate differently across groups of youth, such that contexts that may protect some youth from the negative effects of bullying are not generalizable to all youth. Seven recommendations are offered for monitoring, preventing, and intervening in bullying.