Emerging evidence indicates that parental fatigue is associated with low warmth and increased hostility in parent-child interactions. One possible pathway by which fatigue may impact on parenting behaviour is via parental self-efficacy (PSE), whereby high fatigue may undermine PSE, which is often associated with suboptimal parenting behaviour. The current study sought to explore a model of the relationships between parental fatigue, parenting warmth and hostility, where PSE mediates these relationships and whether the nature of these relationships differ by social or family context.The current sample was drawn from a larger Australian community sample survey on parent well-being and parenting. It consisted of 1143 parents (mothers, n = 1003; fathers, n = 140) of children aged 0-4 years.Path analysis revealed that the relationship between fatigue and parenting warmth and hostility was fully mediated by PSE.These results indicate that fatigue has the potential to negatively influence parenting behaviours that are important for their children's well-being and development, and that fatigue plays a mediating role in this relationship. Implications of the study for psycho-education and interventions targeting the management of parental fatigue are discussed.