The aim of this paper is to assess the frequency of localised primary canine hypoplasia (LHPC) in a sample of 24 subadults from a Neolithic cemetery assemblage located at Man Bac, northern Vietnam (~4000–3500 years BP), and explore the range of factors potentially contributing to the development of this condition. It is found that 41.7% of individuals (20.9% of primary canines) have LHPC, which is similar to the frequency reported in a suite of ancient cemetery series from Neolithic through to Metal Age Thailand. A range of competing aetiological factors considered included trauma to the deciduous canine, ostensibly by way of early childhood exploratory behaviours (e.g. ‘mouthing’ objects), nutritional and dietary deficiencies (especially vitamin A and D), the impact of the mother's health on the developing foetus as well as the effects of premature birth on the developing child. It is concluded that while the aetiology LHPC is multi‐factorial, the reasonably high prevalence of this condition at Man Bac suggests depressed maternal and neonatal health, consistent with a community experiencing high rates of fertility and transitioning to an agricultural subsistence economy. Copyright © 2012 John Wiley & Sons, Ltd.