Previous laboratory research has found that people take more personal responsibility for their performance following success than failure. To extend these findings of a self-serving bias to real-world competitive settings, two field studies were conducted, one with 27 intramural basketball teams and one with 20 pairs of squash players. Players attributed more responsibility to the winners than to the losers for the game outcome. Subsequent laboratory research using observer subjects demonstrated that false information about the outcome of a sporting event was sufficient to produce biased responsibility judgments. Similarly, observers attributed more responsibility to winners than to losers for the outcome of such real world events as wars and economic competitions. The observer data suggest that non-motivational factors are involved in the differential attribution of responsibility to winners and losers. Observers may presume that both parties in a competition intend to win and that more responsibility is given to the individual or team whose outcomes and intentions correspond. A laboratory study supported this hypothesis. (Author/JAC)