This study explored how contact with gay and lesbian persons affects adolescents' attitudes toward them, and whether this association is mediated or moderated by one's acceptance of gender non-conformity. We analyzed survey responses from 456 Dutch adolescents aged 12-15 who reported having no same-sex attractions. Data were collected in 2008 at 8 schools in Amsterdam, the Netherlands. Preliminary analyses showed that contact with lesbian/gay persons outside of school was positively associated with attitudes toward lesbians and gay men. Multilevel analyses showed that acceptance of gender non-conformity mediated rather than moderated the relationship between intergroup contact and sexual prejudice in males. The effect of intergroup contact on females' attitudes toward lesbian women was no longer significant in multilevel analyses. The findings suggest that attention to both intergroup contact and acceptance of gender non-conformity would enhance our understanding of attitudes toward homosexuality in adolescents. (Contains 2 tables and 1 figure.)