Background: Higher levels of insomnia predict greater depression severity among older adults; however. The psychological mechanisms underlying this relationship are unclear. This study tested a path model that explored whether dysfunctional beliefs about sleep and hopelessness mediate. The relationship from insomnia to depression. It was hypothesized that insomnia would predict depression, both directly and indirectly, via dysfunctional beliefs about sleep and hopelessness. Methods: A community sample of 218 independent-living Australian older adults aged from 65 to 96 years completed a self-report questionnaire package. Fro. The initial 218 participants, 171 completed a measure of depression three months later. Results: Path analysis demonstrated that maladaptive sleep beliefs and hopelessness partly explained how insomnia influenced depression, irrespective o. The presence of obstructive sleep apnea and/or restless legs syndrome. Conclusions: An older adult's beliefs about sleep and sense of hopelessness were important psychological factors that helped explain how insomnia related to depression.