Objective This project investigated Māori women's decision making around breastfeeding within the context of whānau attitudes towards breastfeeding in order to describe the dynamic role played by the whānau whānui (extended family) in a woman's decision to breastfeed or not. Methods During late 2004 and early 2005, 30 women who had cared for a newborn within the previous three years and 11 family members were recruited from within Auckland (a major urban area) and small towns and rural areas in and around the Bay of Plenty. Purposive sampling was used to recruit a diverse demographic of Māori women and whānau members. Given the exploratory nature of the study, detailed qualitative data was collected during semi-structured face-to-face interviews with women alone or together with whānau. All participants self-identified as Māori and were over 16 years of age. Ethical approval for the study was obtained from the University of Auckland Human Participants Ethics Committee. Results A diverse range of women were interviewed in terms of age, socio-economic status, gravida, parity, pregnancy wantedness, birthing experience, baby's age and breastfeeding experience. Women who did not want to breastfeed and women who formula-fed their babies from early on were under-represented in this research. The women's partners, mothers, sisters and aunties were cited most often as having a role in the decision to breastfeed and in supporting breastfeeding. Most of the women and whānau thought it was the feeding mother's place to decide if she would breastfeed or not and for how long. Infant feeding usually came up for discussion around ordinary home life and meetings during one-on-one conversations. Sometimes infant feeding was not discussed with whānau until the mother encountered problems. Conclusion This research supports the assertion that whānau are central and that whānau could be mobilised to support healthy choices. Further research is needed to investigate fathers’ experience of maternity services to inform the development of health education materials to prepare partners for their role in supporting breastfeeding. Research should also seek to identify which healthcare policies undermine and minimise the role of the father and other whānau in pregnancy, birthing and infant care. Public health policies that encourage the delivery of health services to whānau in a culturally appropriate, accessible and effective way are important for promoting whānau ora (family health and well-being) and supporting Māori development.