Background: Racial/ethnic disparities in osteoporosis treatment and outcomes are significant concerns for adults aged 65 and older after an incident fracture. However, limited research evaluates how multilevel factors are associated with disparities in receipt of osteoporosis drug therapy (ODT) during the two-years post-fracture. This dissertation evaluated individual, neighborhood, and provider-level factors as potential sources of racial and ethnic disparities in osteoporosis management in the US. Methods: Using 2010-2019 Medicare claims from 722,220 women aged 65+ with an incident osteoporotic fracture, I evaluated racial and ethnic disparities in receipt of ODT over two years and examined effect modification by age and comorbidity. The study population included Non-Hispanic White (NHW; n=663,312), Non-Hispanic Black (NHB; n=35,754), Hispanic (HISP; n=10,726), Asian American/Pacific Islander (AA/PI; n=8,259), and First American/Alaska Native (FA/AN; n=3,971) women. Osteoporosis diagnosis was defined using ICD-9-CM (733.00–733.03,733.09) or ICD-10-CM (M81.0,M81.6,M81.8) codes. Neighborhood deprivation was defined using Area Deprivation Index (ADI) scores. These factors were assessed as potential mediators of racial/ethnic disparities in ODT. Mediation analysis estimated total effect (TE) of race/ethnicity on racial disparities in receipt of ODT at 6, 12, and 24 months. Using a new cross-sectional survey and linear regression, this research also evaluated associations between provider characteristics and osteoporosis knowledge among 103 respondents. Results: Of the 722,022 participants, 62,890(8.7%) received ODT, including 14.1% of AA/PI, 11.2% of HISP, 10.1% of FA/AN, 8.7% of NHW, and 5.4% of NHB women within two-years. Age, but not comorbidity, significantly modified disparities in receipt of ODT (p<.001). Osteoporosis diagnosis was a significant mediator. For instance, NHB compared to NHW women were 25–45% (TE=OR:0.75,95%CI:0.69-0.80) less likely to receive ODT at 24-months, with diagnosis explaining 43.6% of that disparity. ADI was not a significant mediator. Survey results indicated osteoporosis knowledge was higher among specialists (p=.07) and female/non-binary providers (p=.01). Conclusions: ODT disparities persisted for two years post-fracture, especially among NHB women. Improving osteoporosis screening and diagnosis should be examined as a possible way to reduce racial disparities in receipt of ODT. Racial/ethnic disparities may also be affected by variations in providers’ osteoporosis knowledge but further research in this area is needed.