This study investigated three dimensions of sexual orientationidentity, attraction, and behaviorin a national survey of late adolescents. Prevalence rates and the diversity of dimensions of sexual orientation when combined were studied. A representative sample of 3,432 Swedish high school seniors completed an anonymous school-based self-report survey about sexuality, Internet use, and health. Four measures of sexual orientation were includedone for sexual identity, two for attraction (emotional or sexual attraction, romantic attraction), and one for sexual behavior. Prevalence rates of sexual minority orientation varied between 4.3% for sexual behavior (males 2.9%, females 5.6%) and 29.4% for emotional or sexual attraction (males 17.7%, females 39.5%). Different measures of sexual orientation were significantly associated with one another. Bisexual or homosexual orientation was reported by 1.5% of the participants in all four measures and by 17.6% in at least one measure. Researchers need to carefully choose, depending on the research questions under investigation, which dimensions of sexual orientation and which measures they wish to include in their survey. Recommendations based on findings from the study are given.