This commentary describes a national bullying prevention effort, called Stop Bullying Now!, which aims to increase awareness of the problem of bullying and related research findings, and disseminate evidence-based approaches to prevention. Drawing on the special issue's main theme of the social context of bullying, the author describes the process used to develop the Stop Bullying Now! campaign, highlights the importance of interagency approaches to bullying prevention, and provides examples of social marketing and media activities aimed to prevent bullying on a national scale. (Contains 1 table.)