Non-communicable diseases (NCDs) are an increasingly important driver of urban vulnerability in low- and middle-income countries. The paper examined the causal effect of NCD status on household food insecurity across Gauteng’s metropolitan municipalities using the 2024 South African General Household Survey (n = 4,730). Households with NCDs (n = 1,243) were compared to those without (n = 3,487) using propensity score matching to estimate average treatment effects on food insecurity, measured by the Household Food Insecurity Access Scale (HFIAS). The descriptive data indicated low overall food insecurity but revealed significant socioeconomic
differences between groups. After matching, the findings showed clear spatial heterogeneity. NCD status was associated with a marginal reduction in food insecurity in Johannesburg (ATE = - 0.469, p < 0.10) and with higher food insecurity in Tshwane under stricter matching (ATE = 0.636, p = 0.050), while no significant effects were observed in Ekurhuleni or in the pooled sample. Findings support targeted interventions, including income stabilisation, strengthening urban food systems, and integrating food insecurity into NCD care.