The global population is aging, and as the population ages, high-risk alcohol and other drug use, particularly cannabis and prescription medications, is growing among older adults (OA). OA, defined here as 50 years of age and older, have a number of unique vulnerabilities to drug and alcohol use due to both biological as well as psychosocial factors compared to younger adults. Understanding the wide spectrum of these vulnerabilities is important to assessment, diagnosis, and intervention. Specific techniques, assessment tools, and interventions known to be effective in OA are reviewed.