Helping acts, however well intended and beneficial, sometimes involve immoral means or immoral helpers. Here, we explore whether help recipients consider moral evaluations in their appraisals of gratitude, a possibility that has been neglected by existing accounts of gratitude. Participants felt less grateful and more uneasy when offered immoral help (Study 1, N = 150), and when offered morally neutral help by an immoral helper (Study 2, N = 172). In response to immoral help or helpers, participants were less likely to accept the help and less willing to strengthen their relationship with the helper even when they accepted it. Study 3 ( N = 276) showed that recipients who felt grateful when offered immoral help were perceived as less likable, less moral, and less suitable as close relationship partners than those who felt uneasy by observers. Our results demonstrate that gratitude is morally sensitive and suggest this might be socially adaptive.