Osteoarthritis (OA) is the most common joint disease in the US and can increase the risk of depression. Both depression and OA disproportionately affect women, yet this study is one of few on depression prevalence, treatment across age groups, and predictors in women with OA. Data were extracted from the 2011–March 2020 National Health and Nutrition Examination Survey (NHANES). Women aged ≥ 45 years with self-reported osteo- or degenerative arthritis were included. Outcomes were depression (assessed with PHQ-9) and treatment (self-reported pharmacotherapy and mental health services). Logistic regression was used to examine associations between age group, covariates, and outcomes. Overall, depression prevalence was 8%, with higher proportions among those 45–64 years old. Aging was associated with reduced odds of depression (Age 65–79: OR 0.68 (95% CI: 0.52–0.89); Age 80+: OR 0.49 (95% CI: 0.33–0.74); vs. Age 45–54). Of those with a positive depression screen, 21.6% documented some form of treatment. Age group was not statistically different between those treated and those not treated. Women aged 45–64 with osteoarthritis may be at increased risk of depression, and most are not treated. As depression is related to increased pain and risk of rehospitalization, future research should prioritize interventions to increase uptake of depression treatment.