Background: Extreme heat exposure is an increasing public health concern, particularly in the context of climate change. Limited research has explored its impact on children's cognitive outcomes. This study investigates the association between extreme heat exposure and cognitive function in 9–10-year-old children, using data from the Adolescent Brain Cognitive Development (ABCD) study. Additionally, we assess whether this effect is independent of socio-demographic factors such as race, family socioeconomic status (SES), and neighborhood SES. Methods: Data were drawn from the ABCD study, comprising over 10,000 children aged 9–10 years. Cognitive function was assessed through standardized cognitive tests, while extreme heat exposure was estimated using geographic and climate data. Structural equation modeling (SEM) was employed to examine the direct effects of heat exposure on cognitive outcomes and to account for potential confounding variables, including race, family SES, and neighborhood SES. Results: Black families, low SES households, and children from low SES neighborhoods were disproportionately exposed to extreme heat. Extreme heat exposure was significantly associated with lower cognitive function in children, and this association remained robust even after adjusting for socio-demographic factors. Conclusions: Extreme heat exposure is linked to diminished cognitive function in children, particularly among socio-economically disadvantaged and marginalized populations. Given the increasing frequency of extreme heat events due to climate change, future research should further explore these implications for children’s cognitive outcomes. Policy interventions that improve access to cooling infrastructure, expand green spaces, and prioritize at-risk populations are critical to mitigating the adverse cognitive effects of extreme heat in low SES communities.Full article