Internationally there is growing evidence that family structure, and changes in structure, have an impact on children’s health and wellbeing and the intergenerational transmission of inequity. The effects, however, vary by socio-economic context and ethnicity. Using longitudinal data from Growing Up in New Zealand (n = 1349), we examine family structure and change for tamariki Māori during early childhood, and the potential impacts on their development and wellbeing. We find that a stable two-parent family is the primary experience for tamariki Māori, and sole parenthood is transitory. Diverse family trajectories appear to be linked to poorer cognitive and socio-emotional outcomes but are not the main driver. More important are maternal factors, notably age and education, and material hardship. Importantly, higher levels of cultural connectedness among tamariki Māori, which are associated with diverse family forms, seem to promote socio-emotional development. Our study provides further incentive for policy and programmes that centre equity and support access to the determinants of health for tamariki Māori.