A theoretical model in which perceived burdensomeness and thwarted belongingness were hypothesized to account for the association between sexual orientation and suicidal ideation among college students was tested. Among 198 college students (mean age 21.28 years), gay, lesbian, and bisexual students (n = 50) reported significantly higher levels of perceived burdensomeness and suicidal ideation than heterosexual students. The relationship between sexual orientation and suicidal ideation was partially accounted for by perceived burdensomeness, but not thwarted belongingness. This indirect effect was stronger at higher levels of perceived or anticipated rejection due to one's sexual orientation. Implications for intervention and prevention science are discussed. (Contains 3 tables, 1 figure, and 3 footnotes.)