Hearing loss (HL) is highly common in older adulthood, constituting the third most prevalent chronic health condition in this population. In addition to posing a substantial burden to disease and negatively impacting quality of life, an emerging literature highlights that HL is associated with unipolar depression including among older adults. This review outlines evidence examining the HL and depression relationship as well as clinical implications for assessment and treatment of comorbid depression and HL. Although prevalence estimates of comorbid depression in HL vary, as many as 1 in 5 experience clinically relevant depression symptoms. Both cross-sectional and longitudinal studies indicate that HL is related to increased unipolar depression symptoms, although the strength of the association varies between studies. A range of methodological variations, such as inclusion age, severity of HL and assessment of depression, likely underpin this heterogeneity. Overall, however, the evidence clearly points to an association of HL with clinically relevant depression symptoms. The association with the diagnosis of major depression disorder remains less clear and under-researched. HL is also associated with a range of other poor mental health outcomes in older adults, including anxiety and suicidal ideation, and predicts poorer cognitive functioning. Accordingly, assessment and treatment of comorbid depression in HL is pertinent to promote mental well-being among older adults. Currently, evidence regarding best practice for treating depression in HL remains scant. Preliminary evidence indicates that audiological rehabilitation, including use of hearing aids, as well as community-based hearing interventions can also improve mental health. Psychological intervention that enhances communication skills and addresses coping strategies might also be beneficial for this population. Additionally, evidence suggests that online interventions are feasible and may circumvent communication difficulties in therapy associated with HL. Due to poor help-seeking among this population, an enhanced focus on specific and targeted assessment and treatment is likely necessary to ensure reduced mental health burden among older adults with HL.