We compared protective factors among bisexual adolescents with those of heterosexual, mostly heterosexual, and gay or lesbian adolescents. Methods. We analyzed 6 school-based surveys in Minnesota and British Columbia. Sexual orientation was measured by gender of sexual partners, attraction, or self-labeling. Protective factors included family connectedness, school connectedness, and religious involvement. General linear models, conducted separately by gender and adjusted for age, tested differences between orientation groups. Bisexual adolescents reported significantly less family and school connectedness than did heterosexual and mostly heterosexual adolescents and higher or similar levels of religious involvement. In surveys that measured orientation by self-labeling or attraction, levels of protective factors were generally higher among bisexual than among gay and lesbian respondents. Adolescents with sexual partners of both genders reported levels of protective factors lower than or similar to those of adolescents with same-gender partners. Bisexual adolescents had lower levels of most protective factors than did heterosexual adolescents, which may help explain their higher prevalence of risky behavior. Social connectedness should be monitored by including questions about protective factors in youth health surveys.