Health communication can broadly be defined as the use of communication strategies to inform and influence decisions and actions to improve health. Health communication includes clinical encounters, patient education brochures, decision aids, web resources, social marketing campaigns, and social media content. Health decision-making is the cognitive and affective processes through which individuals choose actions directed towards their health, including lifestyle decisions, screening or treatment choices, and long-term illness management. Decisions usually are embedded in the environment and social contexts; often individuals are engaged in shared decision-making with their health-care providers, partners, and family members. This entry provides a brief overview of constructs related to the psychology of health communication and decision-making, theoretical underpinnings, and real-world examples of how these principles are applied.