Contemporary models of health and health behavior recognize the prominent role of emotions in health-related outcomes. Emotional intelligence (EI) reflects individual differences in people’s ability to perceive, understand, and regulate emotions. EI-related competencies promote the use of more adaptive coping strategies in emotionally charged situations, thus contributing to a wide range of desirable life outcomes. This chapter provides a primer on the EI construct and its theoretical, empirical, and applied foundations. Research is then reviewed on the role of EI in three domains of health behaviors: (1) health-risk behaviors, including substance use, risky driving, and risky sexual conduct; (2) health-promoting behaviors, such as eating habits, physical activity, and sleep quality; and (3) adherence to treatment regimens, specifically diabetes self-management and medication compliance among the chronically ill. The scope of this review focuses primarily on studies using EI-specific models and measures, although relevant findings from the cognate literatures on emotion dysregulation and alexithymia are also included. The authors discuss key implications of the research for applications of EI in health promotion and medical practice. Understanding an individual’s EI profile can offer valuable insights into their overall health status, clinical presentation, and responses to intervention and treatment adherence, thus informing more tailored and effective healthcare strategies.