Background: Technical assistance (TA) is increasingly recognized as a strategy to improve substance use disorder (SUD) treatment. This literature review examines the role of TA in strengthening SUD treatment in the United States, on provider needs, barriers, and investment areas to improve access to quality care in California. Methods: A literature review was conducted using six online databases (PubMed, Web of Science, JSTOR, Science Direct, PsycINFO, and Cochrane Library) and manual searching. Eligibility criteria prioritized peer-reviewed studies on TA and SUD treatment outcomes in the United States within the past 15 years from January 2010 to May 2025. The established inclusion and exclusion criteria prioritized peer-reviewed studies focused on improving TA and SUD treatment outcomes in the United States, and included a comprehensive list of search terms. Deductive thematic analysis was used to identify key challenges and recommendations related to TA needs. Results: The initial search yielded 85 articles, which were then narrowed to 18 based on the inclusion criteria. Thematic analysis of 18 relevant articles revealed five overarching TA needs themes: client acuity & access challenges, organizational needs, staffing challenges, treatment & training efficiency support, and workforce development. Key challenges identified included limited funding, workforce shortages, and training gaps, while recommendations emphasized increased funding, expanded training, and integrated care models. Conclusions: TA holds promise for building capacity in SUD treatment, particularly in addressing workforce development, enhancing funding mechanisms, and improving integrated care. In California, a robust and equity-informed TA framework is essential for fostering a more resilient and responsive treatment system for small to medium-sized providers serving vulnerable populations.
