Strong identification with the male gender group, or gender self-esteem, predicts trans prejudice in heterosexual men. Less is known about whether gender self-esteem predicts gay and bisexual men’s attitudes toward trans people. Cisgender gay (n = 88), bisexual (n = 74), and heterosexual (n = 98) men completed measures of trans prejudice and gender self-esteem, as well as beliefs that transgenderism is a psychological disorder and that people are born transgender. The lowest levels of trans prejudice, the least agreement that transgenderism is a psychological disorder, and the most agreement that people are born transgender were reported by gay men, followed by bisexual men, then heterosexual men. Reported levels of teasing were higher for trans women than trans men regardless of men’s sexual orientation. Higher levels of trans prejudice correlated with greater agreement that transgenderism is a psychological disorder and less agreement that people are born transgender for all 3 groups of men. Finally, higher levels of gender self-esteem predicted higher levels of trans prejudice for bisexual and heterosexual men, but not gay men. Future research could further examine factors that underlie gay and bisexual men’s trans prejudice, such as strength of identification with one’s sexual orientation and attitudes toward masculinity and femininity.