The U.S. correctional system is overburdened by individuals suffering from substance use disorders. These illnesses also exact a heavy toll in individual and public health and well-being. Effective methods for reducing the negative impact of substance use disorders comprise critical concerns for policy makers. Drug court treatment programs (DTCs) are present in over 1800 county, tribal, and territorial jurisdictions in the United States, as an alternative to incarceration for offenders with substance use disorders. This review article summarizes available descriptive information on representative drug treatment court populations, summarizes observational studies of drug court participants, and specifically reviews available experimental effectiveness literature on drug treatment courts. The review concludes by examining limitations of the current literature, challenges to conducting research in drug court samples, and potential future directions for research on drug treatment court interventions. Review of non-experimental and quasi-experimental literature regarding the impact of drug treatment courts point toward benefit vs. traditional adjudication in averting future criminal behavior and in reducing future substance use, at least in the short term. Randomized effectiveness studies of drug treatment courts are scant (three identified in the literature on U.S. adult drug courts), and methodological issues arise in combining their findings. These randomized trials failed to demonstrate consistent effect upon re-arrest rates for drug-involved offenders participating in drug treatment court vs. typical adjudication. The two studies examining reconviction and reincarceration, however, demonstrated reductions for the drug treatment court group vs. those typically adjudicated.