In order to compare the relative strengths of sex-role stereotypes and situational cues in the perception and evaluation of leadership, this study investigated the visibility (identifiability) and perception of male and female leaders as a function of group sex composition, level of performance, and rater sex. Through videotapes, 451 introductory psychology students viewed same or mixed-sex three-person groups working interactively on a brain-storming problem. Situational cues (positioning, quantity of verbal participation, quality of verbal inputs) were used to define a male or female as occupying a leadership role, and subjects were asked to indicate whom they believed the group leader was, to evaluate members on leadership and personal attributes, and to rate the group's atmosphere and satisfaction. It was hypothesized that males and females would be equally visible as leaders in groups composed of all same-sex followers or mixed-sex groups composed of one same and one opposite-sex follower. Due to sex-role expectancies, visibility was expected to decrease for female leaders dealing with groups composed of all male followers. Female leaders were expected to receive lower personal evaluations on ratings of leadership attributes. High group performance was expected to lead to more favorable evaluations of all group members, but lower visibility for female leaders of mixed or opposite-sex followers. While rater sex was not expected to affect leader designation, it was hypothesized that female raters would give more favorable personal evaluations of all stimulus persons and of group atmosphere. Results indicated that under these conditions, the person established as the leader through situational cues was seen as the group leader regardless of the sex of the followers that the leader interacted with, the performance level attributed to the group, or the sex of the observer making the judgment. Designated leaders were identified as the leader of the group between 88 and 100 percent of the time, indicating that the techniques used to establish leadership were successful in creating a situation of high leader salience. Results were interpreted as an indication that sex stereotypes may affect evaluations of individuals about whom little is known but sex, but not affect ratings of those for whom relevant behavioral data are available. The variables of leader sex and follower sex had no significant effects on leader evaluations, but did interact on the measures of satisfaction with leader, willingness to work with the group viewed, and expected future performance of the group. On the measure of satisfaction with leader, the sex of the highest-participating follower but not the lowest influenced judgments, making the two types of mixed-sex groups more similar to one of the same-sex groups (specifically the one in which the sex of the highest-participating follower was the same) than they were to each other. Performance level had significant effects on most leader evaluation measures, with leaders of high-performing groups being rated more leader-like, more dominant, more intelligent, and as possessing more task-oriented attributes. High-performance also enhanced ratings of followers, particularly for higher-participating followers. Rater sex did not affect leader designation, but it was found that female raters gave more favorable evaluations of leadership, dominance, and task-oriented attributes.