The success of our political institutions, environmental stewardship and evolutionary fitness all hinge on our ability to prioritize collective-interest over self-interest. Despite considerable interest in the neuro-cognitive processes that underlie group cooperation, the evidence to date is inconsistent. Several papers support models of prosocial restraint, while more recent work supports models of prosocial intuition. We evaluate these competing models using a sample of lesion patients with damage to brain regions previously implicated in intuition and deliberation. Compared to matched control participants (brain damaged and healthy controls), we found that patients with dorsolateral prefrontal cortex (dlPFC) damage were less likely to cooperate in a modified public goods game, whereas patients with ventromedial prefrontal cortex (vmPFC) damage were more likely to cooperate. In contrast, we observed no association between cooperation and amygdala damage relative to controls. These findings suggest that the dlPFC, rather than the vmPFC or amygdala, plays a necessary role in group-based cooperation. These findings suggest cooperation does not solely rely on intuitive processes. Implications for models of group cooperation are discussed.