Social media are designed to be engaging, but often are used as a mechanism by public health organizations and practitioners for mass information dissemination rather than engaging audiences in true multi-way conversations and interactions. In this article we define and discuss social media engagement for public health communication. We examine different levels of engagement for public health communication and consider the potential risks, benefits, and challenges of truly embracing the social component in public health practice. Some implications of engagement for public health communication via social media are addressed, and recommendations for future work and research are proposed.