Using data collected from a sample of 50 academic departments over the years 1977–88, the authors test several hypotheses about the effects of departmental gender composition on faculty turnover. They find that as the proportion of women in a department grew, turnover among women also increased, confirming the prediction that increases in the relative size of a minority will result in increased intergroup competition and conflict. The evidence also suggests, however, that when the proportion of female faculty reached a threshold of about 35–40%, turnover among women began to decline. The proportion of women had a negligible or negative impact on turnover among male faculty. The authors discuss the implications of this research for the implementation of affirmative action policies.