Background: Older adult prescription tranquilizer/sedative misuse is understudied, despite evidence of increased misuse prevalence and significant associated consequences (e.g., suicidal ideation). Identification of misuse sources could limit such misuse by offering policymakers and clinicians targets to limit diverted tranquilizer/sedative medication. Objective: To establish the prevalence of tranquilizer/sedative misuse sources in older adults and investigate associated poor outcomes. Methods: Data were from the 2009-14 National Survey on Drug Use and Health, including participants endorsing one or more past-month tranquilizer/sedative misuse sources (n = 3,162) with older adult (50-64 and 65 and older; n =160) tranquilizer/sedative source prevalence estimated and compared to younger cohorts. Results: Adults 65 and older had the greatest physician source use (38.2%) across ages. Physician source use in those 50 and older, relative to those obtaining medication from friends/family for free, was linked to a higher prevalence of both past-year prescription opioid misuse (58.6% versus 34.9%) and serious psychological distress (50.1% versus 11.6%). Conclusions/Importance: Physician source use is particularly prevalent in adults 65 and older, and adults 50 and older using physician sources appear at elevated risk of consequences. Careful monitoring of psychiatric symptoms in older adults receiving tranquilizers/sedatives appears warranted. Older adults use a unique pattern of tranquilizer/sedative misuse sources, as compared to younger groups, further signaling that older adult misuse processes differ from those in younger groups.