Insomnia has been identified as a risk factor for suicide. Apart from its indirect influence on suicide risk through comorbid psychiatric illnesses, there is also strong empirical evidence that insomnia is an independent risk factor for suicide. Insomnia may affect suicide through different mechanisms, such as mood dysregulation, hopelessness, impulsivity, and sleep deprivation. Cognitive-behavioral therapy for insomnia (CBTI) is an evidence-based, non-pharmacological treatment that is effective in treating both primary and comorbid insomnia disorder. Treatment effects of CBTI can be extended to alleviate suicidality by improving sleep disturbance. Through a literature review, we summarize available data which suggests that CBTI may decrease suicidality risk, and provide clinical implications about utilizing CBTI for high risk suicidal patients.