Children living in socioeconomically disadvantaged communities face distinct stressors when compared to those from more advantaged backgrounds. Research indicates higher levels of child well-being may buffer against the negative effects of stress and adversities, with supportive teacher behaviors playing a key role in promoting well-being. However, the mechanisms underlying these connections remain unclear. Extending past research linking teacher behaviours and well-being, the present study included emotion regulation as a potential candidate mechanism that might account for these connections. Questionnaire data were collected from 508 pupils (265 female, M[subscript age] = 9.9) in 31 classrooms across 8 primary schools in low-socioeconomic neighbourhoods of New Zealand. Utilising multilevel modelling the study found that teacher support significantly predicted emotion regulation and well-being, and that teacher support indirectly predicted well-being through emotion regulation. Both emotion regulation and teacher behaviours are amenable to intervention; thus, a better understanding of how they work together to predict well-being is likely to inform future intervention efforts to promote children's well-being.