This paper reports experiments which examine attributions of leadership quality due to differences in situations. Subjects played an abstract coordination game which is analogous to some organizational situations. Previous research showed that when large groups play the game, they rarely coordinate on the Pareto-optimal (efficient) outcome, but small groups almost always coordinate on a Pareto-optimal outcome. After two or three periods of playing the game, one subject who was randomly selected from among the participants to be the "leader" for the experiment was instructed to make a speech exhorting others to choose the efficient action. Based on previous studies with small and large groups, we predicted that small groups would succeed in achieving efficiency and large groups would fail. Based on research on the fundamental attribution error in social psychology, we predicted that the leaders would be credited for the success of the small groups, and blamed for the failure of the large groups. The effects of the leaders in improving coordination were, as predicted, overshadowed by the situational variable (group size). Nonetheless, there was an "illusion of leadership": subjects attributed differences in outcomes between conditions to differences in the effectiveness of leaders. In a second experiment, subjects in both large and small groups coordinated efficiently, but gave less credit to the second leader than the first