Objectives. We tested unique contribution of trait self-control, implicit self-control, and lay beliefs in self-control beliefs to the prediction of health-related behaviours. We also tested whether relations between trait self-control and health-related behaviour, and between implicit self-control and health-related behaviours, were moderated by self-control beliefs.Design. Cross-sectional, correlational.Methods. Students (N = 176) completed self-report measures of trait self-control, lay beliefs that self-control is limited or non-limited, non-planning, participation in health-related behaviours (impulsive eating, impulsive drinking, exercise avoidance, watching diet, alcohol consumption, physical activity participation), and demographic variables. Participants also completed a measure of implicit self-control using an implicit association test.Results. Analyses indicated significant negative relations between of implicit self-control and impulsive drinking and alcohol consumption. We also found a positive relationship between implicit self-control and exercise behaviour, and a negative relationship between implicit self-control and impulsive eating, both of which fell marginally short of statistical significance. Trait self-control significantly predicted all behavioural measures, and attenuated relations between implicit self-control and health-related behaviour. We found no relations between of lay beliefs in self-control and health-related behaviour. Moderated path analyses revealed that lay beliefs in self-control moderated relations between trait self-control and impulsive drinking, implicit self-control and exercise avoidance, and implicit self-control and physical activity participation.Conclusions. Findings suggest that trait self-control was a consistent correlate of health-related behaviour, while the size of relationships between implicit self-control and health-related behaviours was small. Strength of relations between trait self-control and health-related behaviours may depend on whether or not individuals believe self-control is limited.