Children (n = 133, aged 8–13) were interviewed about helping situations that systematically varied in recipient's need for help and the costs for the helper. In situations where helping a peer involved low costs, children perceived a moral obligation to help that was independent of peer norms, parental authority, and reciprocity considerations. When helping a peer involved high costs this overpowered the perceived obligation to help, but only in situations involving low need and when in line with reciprocity. When both need and costs were high, younger children expressed stronger moral indignation while older children were less negative and reasoned in terms of other solutions. Furthermore, stronger moral indignation was related to more advanced social perspective taking skills when need and costs were high.