Sex differences in attitudes toward homosexuality were examined using Glass's d as an estimator of effect size. There was a small mean effect (d = .207) indicating that males have more negative attitudes than females toward homosexuals. However, this effect was found to decrease in magnitude when sample size was controlled for, with larger studies being less likely to have a sex difference. Year of publication was also found to be related to the effect sizes with more recent studies tending to show a larger effect size. Sex of target is also discussed as a potentially important variable.