Objectives Obese women have lower breastfeeding initiation and maintenance rates than healthy weight women. Research generally focuses on biomedical explanations for this. Psychosocial factors including body image and well-being after childbirth are less well understood as predictors of breastfeeding. In obese and healthy weight women, we investigated changes in body image between 72 hrs post-delivery and 6–8 weeks post-natal, studying how women's body image related to breastfeeding initiation and maintenance. We also investigated how psychological distress was related to body image. Design Longitudinal semi-structured questionnaire survey. Methods Body image and psychological distress were assessed within 72 hrs of birth and by postal questionnaire at 6–8 weeks, for 70 obese and 70 healthy weight women initiating exclusive (breastmilk only) breastfeeding or mixed feeding (with formula milk) in hospital. Breastfeeding was re-assessed at 6–8 weeks. Results Obese women were less likely to exclusively breastfeed in hospital and maintain breastfeeding to 6–8 weeks. Better body image was related to maintaining breastfeeding and to lower post-natal psychological distress for all women, but education level was the most significant predictor of maintenance in multivariate regression including body image and weight status. Body image mediated, but did not moderate the relationship between weight and breastfeeding maintenance. Body image was lower overall in obese women, but all women had low body image satisfaction around childbirth, reducing further at 6–8 weeks. Conclusions Health professionals should consider women's body image when discussing breastfeeding. A focus on breast function over form may support breastfeeding for all women