In recent years, there has been an increase in outbreaks of diseases that are preventable by vaccination. As vaccination involves behavior, behavior analysts are uniquely positioned to contribute solutions to this socially significant problem. The present article explores a behavior-analytic approach to understanding the function of the behavior of both people who have their children vaccinated and those who do not have their children vaccinated, and potential interventions to increase vaccination rates. An introduction to the problem is followed by a brief history of the antivaccination movement. In our analysis, a failure to vaccinate is conceptualized as a noncompliance response (i.e., medical nonadherence), and conditions giving rise to that noncompliance are evaluated. In this process, the roles of avoidance, the functional-altering impact of rule-governed behavior, relational frames, and countercontrol are considered. Potential solutions informed by applied behavior-analytic literature, including contingency management and behavioral safety, are discussed.