Background: Buprenorphine is a key medication to treat opioid use disorder, but little is known about how treatment quality varies across sociodemographic groups. Objective: We examined measures of treatment quality and explored variation by sociodemographic factors. Methods: We used Medicaid MAX data from 50 states from 2006 to 2014 to identify buprenorphine treatment episodes (N ¼ 317,494). We used multivariable logistic regression to examine the quality of buprenorphine treatment along four dimensions: (1) sufficient duration, (2) effective dosage, and concurrent prescribing of (3) opioid analgesics and (4) benzodiazepines. We explored how quality varied by race/ethnicity, age, sex, and urbanicity. Results: In adjusted models, compared to non-Hispanic White individuals, non-Hispanic Black and Hispanic individuals had lower odds of receiving effective dosage (aORs ¼ 0.79 and 0.89, respectively) and sufficient duration (aORs ¼ 0.64 and 0.71, respectively), and lower odds of concurrent prescribing of opioid analgesics (aORs ¼ 0.86 and 0.85, respectively) and benzodiazepines (aORs ¼ 0.51 and 0.59, respectively). Older individuals had higher odds of sufficient duration (aORs from 1.21-1.33), but also had higher odds of concurrent opioid analgesics prescribing (aORs from 1.29-1.56) and benzodiazepines (aORs from 1.44-1.99). Females had higher odds of sufficient duration (aOR ¼ 1.12), but lower odds of effective dosage (aOR ¼ 0.77) and higher odds of concurrent prescribing of opioid analgesics (aOR ¼ 1.25) and benzodiazepines (aOR ¼ 1.16). Compared to individuals living in metropolitan areas, individuals living in non-metropolitan areas had higher odds of sufficient duration (aORs ¼ 1.11 and 1.24) and effective dosage (aORs ¼ 1.06 and 1.33), and lower odds of concurrent prescribing (aORs from 0.81-0.98). Conclusions: Black and Hispanic individuals were less likely to receive effective buprenorphine dosage and sufficient duration. Quality results were mixed for older and female individuals; although these individuals were more likely to receive treatment of sufficient duration, they were also more likely to be concurrently prescribed potentially contraindicated medications, and females were less likely to receive effective dosage. Findings raise concerns about adequacy of care for minority and other at-risk populations.