Background: Suicidality in adolescents is a growing concern and is currently a public health issue in Chile and the world. Objective: To determine the association between the risk of suicidality with self-harm, sociodemographic parameters (that is, gender and type of school), psychosocial variables, and social and family support in Chilean adolescents. Methods: In a cross-sectional study, 829 (377, 45.5% girls) children/adolescents between 10 and 19 years of age participated. Suicidality, self-esteem, health-related quality of life (HRQoL), and social support perception were evaluated by standard, validated questionnaires. The presence of self-harm, dating violence, and family dysfunction was also evaluated through a self-report survey. Results: Suicidality risk was related to low self-esteem (OR = 9.73; 95%; CI = 6.62–14.28; p p p p p p p p = 0.011). Conclusion: Suicidality was associated with self-harm, low social, psychological and family well-being, and/or feeling mistreated by a boyfriend/girlfriend.