The Theory of Planned Behaviour is a prominent theory to understand social behaviours. Based on this theory, it can be predicted that people have greater intention to gamble if they have stronger positive attitudes towards gambling and weaker beliefs in their ability to control gambling behaviour. Greater intention then predicts gambling behaviour. The aim of this study was to examine the role of beliefs in free will and determinism in the Theory of Planned Behaviour. The researchers found that beliefs in free will did not influence gambling behaviour directly. But people with stronger beliefs in free will had weaker attitudes towards gambling and stronger beliefs in their control over gambling behaviour. Consequently, they had less intention to gamble. Intention in turn predicted gambling behaviour. Beliefs in determinism did not have an influence on either gambling intention or behaviour.