<h3>Introduction</h3> A substantial proportion of older adults will experience depression (including major depressive disorder and subsyndromal depressive symptoms), yet depression remains underdiagnosed and undertreated among older adults. Behavioral Activation is an effective, empirically-validated, first-line treatment for mild to moderate depression. Behavioral activation is a patient-centered intervention designed to decrease depressive behavior (e.g. social isolation, physical inactivity) and increase engagement in pleasurable activities (e.g. hobbies, family time). The objective of this scoping review is to evaluate the gaps in the literature and knowledge base regarding the implementation contexts, target populations, delivery modalities, assessment methods, and effectiveness of behavioral activation as a treatment for depression and/or anxiety among older adults, including both inpatient and outpatient settings. <h3>Methods</h3> We performed a scoping review and searched for peer-reviewed articles published from 1990 to 2020. The keywords and their combinations (e.g., depression, anxiety, elder(s), elderly, geriatric, older adult(s), age, aged, aging, behavio(u)ral activation) were used in search engines including the following but not limited to PubMed, PsycINFO, and Cochrane. Our search strategy identified 423 results; after removing duplicates, 232 results remained. Currently, we are evaluating the titles and abstracts using broad inclusion criteria to ensure that all relevant behavioral activation relevant to geriatric depression and/or anxiety are included. All types of studies and publications (e.g. randomized clinical trials, cohort studies, case controls, reviews, etc.) that focus on behavioral activation as an intervention or primary focus are being included in this comprehensive search. Studies have to include participants > 50 years old with either clinically diagnosed depression and/or anxiety at or above a pre-defined cut-point on a validated symptom scale (e.g., PHQ-9: >5 and GAD-7: >5). <h3>Results</h3> This scoping review will chart the landscape of literature relevant to behavioral activation for older adults with depression and/or anxiety. The literature will be reviewed in terms of study setting (e.g., community or outpatient settings, inpatient psychiatric units, assisted living facilities); study type (including randomized clinical trials, as well as observational studies, cohort studies, case controls, cross sectional, etc.); mode, frequency, and duration of intervention delivery; type and training of providers; assessment methods; and outcomes. Reviews will be examined for themes and consistency in synthesis of findings. Particular attention will be paid to identifying gaps in the literature where further work is needed to broaden the reach and impact of this promising intervention. <h3>Conclusions</h3> Scoping reviews represent a compelling method for evaluating existing literature and identifying gaps for future study. The present scoping review will synthesize the identified literature, in the hope of helping not only clinicians who work closely with older adults, but also researchers wishing to pursue studies in this area. Given a burgeoning older adult population and a paucity of geriatric mental health providers, clinical guidelines offering alternative nonpharmacologic therapy can be effective and cost-effective for clinicians and healthcare systems. Given the COVID-19 pandemic and the consequent escalation in social isolation among older adults, it is also hoped that this scoping review will identify promising avenues and methods for adapting behavioral activation in myriad ways—i.e., through implementation via telehealth platforms—to the older adult population. <h3>Funding</h3> Not applicable