The current study examined the association between effortful control and a well-studied neural index of self-regulation, the N2 event-related potential (ERP) component, in toddlers. Participants included 107 toddlers (44 girls) assessed at 30, 36 and 42 months of age. Participants completed a Go/NoGo task while electroencephalography data were recorded. The study focused on the N2 ERP component. Parent-reported effortful control was examined in association with the NoGo N2 ERP component. Findings suggest a positive association between the NoGo N2 component and the inhibitory control subscale of the wider effortful control dimension, suggesting that the N2 component may index processes associated with temperamental effortful control. This article is part of the theme issue ‘Diverse perspectives on diversity: multi-disciplinary approaches to taxonomies of individual differences’.