Breastfeeding can play a key role in the reduction of obesity, but initiation and maintenance rates in women with a Body Mass Index (BMI) of ≥30kg/m2 are low. Psychological factors influence breastfeeding behaviours in the general population, but their role is not yet understood in women with a BMI ≥30kg/m2. Therefore, this review aimed to systematically search and synthesise the literature which has investigated the association between any psychological factor and breastfeeding behaviour in women with a BMI ≥30kg/m2. The search identified twenty eligible papers, reporting sixteen psychological factors. Five psychological factors were associated with breastfeeding behaviours: intentions to breastfeed, belief in breastmilk’s nutritional adequacy and sufficiency, belief about other’s infant feeding preferences, body image and social knowledge. It is therefore recommended that current care should encourage women to plan to breastfeed, provide corrective information for particular beliefs, and address their body image and social knowledge. Recommendations for future research include further exploration of several psychological factors (i.e. expecting that breastfeeding will enhance weight loss, depression, anxiety and stress) and evidence and theory based intervention development.