While there appears to be overwhelming evidence, in the literature on group/team dynamics, that individuals exert less than 100% effort when acting as members of a group (“social loafing”), there have been very few investigations concerning group gender composition and the effect of individual effort. The purpose of this study was to investigate the social loafing phenomenon focusing on the behavior of males and females performing a physical task as members of gender-specific teams. Twenty male and 27 female, college students served as subjects. Their task was to pull, with maximum effort, a rope which was attached to a hidden spring scale. Each subject performed the task in four counterbalanced conditions: (1) alone; (2) with 2 male teammates; (3) with 2 female teammates; and (4) with one male and one female teammate. All teammates were actually confederates of the experimenter who did not exert force on the rope; therefore, only the subjects’ individual effort, as measured by the spring scale, was recorded for each condition. As predicted, repeated measures ANOVA revealed a significant difference in pulling effort between the 4 conditions (for both the male and female subjects) (p<01). However, Post Hoc procedures, consisting of pairwise comparisons utilizing the Bonferroni method to protect against inflation of the per family type I error rate, had surprising results. Both males and females were found to pull harder when acting as members of a group. Most interestingly, both male and female subjects exerted the least effort in the individual condition and the most effort when they were members the all male team. In fact, significant differences in performance was observed between the individual condition and the all male teammate condition for both the male and the female subjects (p<.01 for both male and female subjects). In contrast to past investigations of the social loafing phenomenon, the results of this study suggest that participation in small gender-specific groups, especially all male teams, has a facilitative affect on the individual effort of both men and women. Future investigations utilizing larger groups and different physical tasks is suggested. Keyword(s): gender issues