--- - |2 Abstract How does war influence moral judgments about harm? While the general rule is “thou shalt not kill,” war appears to provide an exception to the moral prohibition on intentional harm. In three studies (n = 263, n = 557, n = 793), we quantify the difference in moral judgments across peace and war contexts, and explore two possible explanations for the difference. The findings demonstrate that third‐party observers judge a trade‐off of one life for five as more morally acceptable in war than in peace, especially if the one person is from an outgroup of the person making the trade‐off. In addition, the robust difference in moral judgments across “switch” and “footbridge” trolley problems is attenuated in war compared to in peace. The present studies have implications for moral psychology researchers who use war‐based scenarios to study broader cognitive or affective processes. If the war context changes judgments of moral scenarios by triggering group‐based reasoning or altering the perceived structure of the moral event, using such scenarios to make decontextualized claims about moral judgment may not be warranted. - European Journal of Social Psychology, EarlyView.