Substance use disorder remains a United States public health concern, particularly for minoritized populations. This systematic review explores the relationship between workforce diversity, cultural competency, and the quality of substance use disorder treatment for minoritized populations. Studies published between 2003 and 2023 were analyzed and nine studies met inclusion criteria. Findings reveal conflicting evidence about the impact of workforce diversity and cultural competency on quality outcomes. While some studies suggest positive associations, others report no relationship or adverse effects. Moreover, inconsistencies in research methodology limited comparative analyses. The literature predominantly focuses on Hispanic/Latinx populations, leaving gaps in understanding other minoritized populations' experiences. Despite national initiatives promoting health equity and diversity, federal research funding regarding substance use disorder treatment for minoritized populations remains limited. This review calls for further research to inform policy and practice, emphasizing multi-agency collaboration, standardized measures of cultural competency, and targeted funding to address disparities in treatment quality outcomes for minoritized populations.