Depression and suicidal thoughts and behaviors are prevalent among youth today. The current study sought to further our understanding of the correlates of depression and suicidality by assessing the relationship between restrictive emotionality (difficulty understanding and expressing emotions) and depressive symptoms and suicidal ideation and attempts among adolescents. A large group of high school students (n = 2189, 58.3% male; 13–18 years of age) completed a self-report survey as part of a 2-stage suicide screening project. Logistic regression analyses were used to assess the association between restrictive emotionality and depressive symptoms, suicidal ideation, and suicide attempts. Those reporting high restrictive emotionality were 11 times more likely to have elevated depressive symptom scores, 3 times more likely to report serious suicidal ideation (after controlling for depressive symptoms), and more than twice as likely to report a suicide attempt (after controlling for depressive symptoms) than those reporting low restrictive emotionality. Restrictive emotionality partially mediated the relationship between depressive symptoms and suicidal ideation and behavior. The pattern of association between restrictive emotionality and the outcome variables was similar for boys and girls. Restrictive emotionality is highly associated with elevated depressive symptoms and suicidal thoughts and behaviors among high school students, and may be a useful specific target in prevention and treatment efforts.