Although same-sex marriages are legally recognized in many Western societies, prejudices against gay men and lesbians remain and already appear in adolescents. Since a negative attitude toward gay men and lesbians is likely to foster malevolent behaviors, we investigated predictors of homonegativity in adolescents aged between 14 and 16 years. Regression analyses revealed that Muslim religious denomination -- but not another or no religious denomination -- and traditional gender roles substantially explained variance in homonegativity, followed by contact with gay and lesbians friends, religiosity, and gender. Migration background, socioeconomic status, and contact with homosexual family members were not found to be predictors of homonegativity. Implications of these findings are discussed, in particular, the importance of cautiously interpreting these correlational data that do not allow for a straightforward causal interpretation.