BackgroundAmbivalence in attitudes towards life and death are associated with suicide ideation (SI) among adolescents. However, previous research was mainly cross‐sectional and did not examine through which psychopathological mechanisms (such as depression) attitudes towards life and death are associated with SI.ObjectiveThe current longitudinal study examined the mediating role of depression at follow‐up in the association between attitudes towards life and death at baseline and SI at follow‐up among at‐risk adolescents referred to an outpatient psychiatric clinic.Methods129 adolescents aged 10–18 years (75.2% females) with a history of suicidal thoughts and behaviors were assessed at clinic intake and 1 month follow‐up (80% retention rate at follow‐up). All participants completed a questionnaire assessing attitudes towards life and death and SI severity at clinic intake, and depression and SI severity at 1 month follow‐up.ResultsWhile controlling for SI severity at intake, attraction towards life at baseline, rather than attraction and repulsion towards death at baseline, led to higher SI severity at follow‐up, while depression at follow‐up fully mediated this association.ConclusionsAttitudes towards life, as well as depression play critical roles in the development of SI among adolescents. Interventions targeting reasons for living and promoting meaning of life may be beneficial in preventing depression and SI.