In the United States, suicidal ideation is an issue for high school–age youths. Research supports that youths who have learning difficulties and who are at risk of high school dropout are at greater risk for suicidal ideation. Although alternative high schools address both student academics and emotional health, they are underused, nonclinical settings for understanding and addressing suicidal ideation. This study aimed to examine the impact of student identity, external stressors, and academic self-concept on suicidal ideation among sexual and ethnic minority and underserved students enrolled in an alternative education public high school. The student sample (N = 103) completed a onetime survey comprised of the Suicidal Ideation Questionnaire-Junior, the Cultural Assessment of Risk of Suicide, the Coddington Life Events Scale for Adolescents, and the Piers Harris 2. Results of hierarchical linear regression indicated that identifying as nonheterosexual and experiencing discrimination were associated with greater student reporting of suicidal ideation. Identifying as Latino and other non-White was associated with lower reporting of suicidal ideation. Controlling for student demographics and external stressors, positive academic self-concept was associated with a lower reporting of suicidal ideation. Findings have future implications for health social work, suicide prevention and intervention, and education policy.