There is mounting empirical evidence to suggest that adults are intuitively cooperative. When presented with a cooperative dilemma between self-maximizing and benefitting the common good, decisions made quickly are more likely to be cooperative, whereas slow decisions tend to favor self-interest. To investigate the ontogenetic origins of intuitive cooperation, we examined the development of intuitive cooperation in middle childhood. We presented 150 children (7-12 years of age) with an online child-friendly public goods game where participants had a choice between giving two resources to themselves or four to their group. Participants were assigned to one of three decision time conditions; speeded, neutral, or delayed. We found that when decisions were speeded, children were more likely to cooperate compared to when decisions were unconstrained or delayed. Furthermore, children's intuitive choices only favored cooperation if they believed their peers were also cooperative. This pattern of findings held across the age range included in this study. Our findings suggest that in middle and late childhood, children are intuitively cooperative when making decisions to benefit the common good.