Communication interventions (CIs) utilize a combination of activities to promote and sustain positive behaviors among a specific audience. These activities, which will be referred to as communication strategies, may include educational programs, health messages, or policies. Communication strategies can be implemented in a variety of settings depending on the objective(s) of the intervention and the target audience. This entry distinguishes campaigns from interventions, discusses the roles that theory plays in the development of CIs, and explains the four-phase process of conceptualizing CIs.