Objective Problems sleeping and stress are known to contribute to the development of suicide ideation. However, it is unclear how these risk factors interact longitudinally. The purpose of this study was to determine the impact of problems sleeping on the development of suicide ideation in adolescence one year later and how the relationship changes with the addition of stress as a moderator. Method Data were collected from 153 adolescents (M age = 12.8, SD = 1.6) over three years as part of a larger study. Participants completed the MINI-Kid and Youth Self-Report, which were used to assess for suicidality. The Stress scale of the YSR was used to measure stress. Participants also completed the Adolescent Sleep Wake Scale, which was used to assess their perceptions of their sleep quality. Results Logistic moderation analyses demonstrated a significant interaction between ASWS and YSR Stress in the prediction of suicide ideation one year later, Wald χ2(1)=4.57, OR = 0.68, p < 0.05. Results demonstrated higher odds of endorsing SI as stress increased when sleep quality was poor (OR = 21.51) compared to when sleep quality was high (OR = 4.03), suggesting that adequate sleep may act as a protective factor against suicide ideation. Conclusions The results are indicative of long-term consequences of sleep on adolescent mental health, particularly when faced with high levels of stress. These results may have significant clinical implications for suicide prevention efforts as this relationship may help identify at-risk adolescents prior to the initial experience of suicide ideation.