<p>Aerobic fitness and body composition are modifiable factors that independently relate to inhibitory control, with higher aerobic fitness associated with enhanced performance and higher body fat associated with poorer inhibitory control in children. This study examined these factors as independent predictors of behavioral and neuroelectric outcomes during a Go/NoGo task. One hundred and two preadolescent children (mean age: 10.07 ± 0.67 years) completed VO₂peak assessments and DXA scans before performing a Go/NoGo task while ERPs were recorded. Linear regressions and mixed-effects models examined main and interaction effects of fat-free aerobic fitness (FFVO₂peak) and body fat percent on behavior, N2 and P3 amplitude and latency across seven midline electrode sites. Higher aerobic fitness was associated with greater NoGo accuracy, while body composition was unrelated to behavioral performance. Aerobic fitness showed topographic interactions with N2 and P3 amplitude during the Go task and with N2 amplitude during the NoGo task, reflecting greater neural resource allocation at fronto-central and centro-parietal sites. Body composition showed a topographic interaction with NoGo P3 latency, with higher body fat associated with shorter latencies. These findings demonstrate dissociable topographic effects of aerobic fitness and body composition on inhibitory control, suggesting distinct pathways of neurocognitive influence in preadolescent children.</p>