<p>Limited research has examined the socioeconomic gradient in children’s cognitive development in Vietnam. This study uses household total and food expenditures as key measures, addressing the limitations of income and wealth indices. Drawing on panel data from the Young Lives Study and employing a fixed effects estimation approach, the study found that both total and food expenditures per capita are positively and significantly associated with children’s cognitive abilities, as measured by the Peabody Picture Vocabulary Test (PPVT). However, the magnitude of these effects is modest, indicating that increases in household expenditure translate into relatively small improvements in cognitive scores. Heterogeneity analysis indicates no gender differences, with boys and girls showing comparable cognitive gains as household expenditure increases. In contrast, the association varies by age, with the strongest link observed in early childhood and diminishing as children grow older. Moreover, the study found that children from the lowest-expenditure households face the largest deficits in cognitive development. These findings highlight the importance of policies that support household economic capacity and target early childhood as an important window for cognitive development, especially children in early childhood and children from disadvantaged households.</p>