This chapter advocates that public health engage communities in the work of improving the health of members. If done well, community engagement is an effective strategy for achieving public health goals in all kinds of communities including rural towns and villages, worksites, schools, civic and faith-based groups, and others. Worksite wellness programs have been especially successful models for engagement. Community engagement is distinguished from social marketing and other non-engaged approaches to impacting the health attitudes, behaviors, and beliefs that result in poor health. The chapter describes some of the tactics for community engagement including integrating primary care and public health, as well as employing community health workers to facilitate health improvement efforts. It reviews the three major approaches for changing risky behaviors. The chapter then discusses the five groups of communities and presents the nine principles of community engagement. It also details the principles of comprehensive worksite wellness programs.