Objectives. The objective of the current study is to examine the determinants of breakfast consumption with the application of the Theory of Planned Behaviour (TPB; 1991) and investigate the additional variables of past behaviour and executive function. Design. A prospective 1-week study investigating the predictive ability of TPB variables, past behaviour and executive function was utilized. Methods. Ninety-six participants were administered two measures of executive function (response inhibition and planning) and completed self-report questionnaires regarding their attitudes, subjective norms, perceived control, intentions and past behaviour of breakfast consumption. One week later, participants returned a follow-up questionnaire on their behaviour. Results. The result of the study showed that the TPB significantly predicted intentions and prospective behaviour of breakfast consumption, however, past behaviour was found to be the strongest predictor of future behaviour. Considering executive function, response inhibition was not found to predict behaviour, however, planning ability explained unique variance in behaviour and moderated the association between intention and behaviour. Conclusions. The findings support the use of the TPB in explaining breakfast eating habits, and suggest that executive function of planning may be somewhat useful to predict this behaviour. The significance of past behaviour also suggests that breakfast consumption may commonly be a stable, habitual behaviour that may undermine the need for self-regulation. Implications for creating behavioural-change interventions are discussed.