Two experiments investigated conditions under which participants drew outcome-biased inferences about ingroups and outgroups. Participants read about ingroup and outgroup targets whose success or failure was in¯uenced by an arbitrary decision rule. In Experiment 1, ingroup and outgroup members experienced two inconsistent outcomes (®rst success and then failure, or vice versa) despite almost identical performances. After reading about the ®rst performance participants made outcome-biased inferences, but when the role of the decision rule became obvious inferences became group-serving. That is, outcomes continued to in¯uence inferences when they cast the ingroup in a positive light (as when initial failure was followed by success) but failed to aect inferences when they were detrimental to the ingroup (as when initial success was quali®ed by later failure). In contrast, inferences about outgroups were outcome-biased when failure followed success, but not when success followed failure. The results of Experiment 2 showed that outcome biases in¯uenced inferences when decision rules produced outcomes that promoted the ingroup but not when they produced outcomes that hurt the ingroup. No such bene®t occurred for outgroups. The results con®rm the impact of motivational concerns such as ingroup bias on the occurrence of outcome biases in inferences.