Two hundred and twenty-six heterosexual participants (115 women and 111 men) were asked to indicate their attitude toward gender-roles, their perceived similarities with gay men, and their attitude toward gay men (i.e., sexual prejudice). As expected, male participants showed more sexual prejudice than female participants, and perceived dissimilarities were related to a greater sexual prejudice. Support for gender-roles was related to sexual prejudice for male participants, but not for female participants. More interestingly, the three-way interaction suggested that perceived similarities moderated the link between gender-roles and sexual prejudice among heterosexual men, but not among heterosexual women. Attitude in favor of traditional gender-roles was related to sexual prejudice for male participants who perceived gay men as different, but not for those who perceived gay men as similar. These findings are discussed in terms of the defensive function of men's attitude toward homosexuality as a result of threat to masculinity.