Philosophers and theologians have long distinguished between acts a good person is obliged to do, and those that are supererogatory-going above and beyond what is required. Across three studies (N = 796), we discovered a striking developmental difference in intuitions about such acts: while adults view supererogatory actions as morally better than obligatory actions, children view fulfilling obligations as morally better. This difference did not stem from differing views of what is obligatory-children agreed that supererogatory acts were not required. And this difference remained even when the very same actions were framed as either supererogatory or obligatory. These findings suggest that the intuition that supererogatory acts are especially morally good might be late-emerging and culturally specific.