Past research indicates that social exclusion leads to self-control failure. The present research examined the neural substrates of this effect. Participants were randomly assigned to either a social exclusion (n=15) or control (n=15) condition. Self-control was assessed by having participants solve 180 moderately difficult math problems while measuring how quickly they identified a supplied answer as correct or incorrect. Magnetoencephalography (MEG) was used to assess neural activity during this task. Socially excluded participants showed lesser activity in occipital and parietal cortex from 100-350 ms after the presentation of the math problems. When presented with the answers, socially excluded participants showed lesser activity in several regions, including occipital, parietal, and right prefrontal cortex from 100-300 ms post-stimulus. Furthermore, activation in the parietal and right prefrontal cortex mediated exclusion-control performance differences on math problems. The findings suggest that social exclusion interferes with the executive control of attention, and this effect is manifest in specific aspects of cognitive performance and brain function.