Drug courts provide what is often a final opportunity for justice-involved persons suffering from substance use disorders to avoid the criminogenic effects of incarceration and the severe health threats associated with substance use, including death. All persons must be provided the same opportunity to participate and succeed in these courts, regardless of their race, ethnicity, assigned gender at birth, age, gender identity and sexual orientation. Research evidence indicates that disparities in drug court processing based on demographic characteristics of participants may be widespread, contrary to most concepts of fairness, particularly those espoused by the National Association of Drug Court Professionals (NADCP). The Equity and Inclusion Assessment Tool (EIAT) described in this article is designed to assist drug courts to determine whether equivalent access to drug court and equivalent retention in drug court exist among all ethnic, racial, and gender groups. This article describes how the EIAT emerged from earlier work by NCSC with a number of states to develop a performance measure that assessed Access and Fairness in drug courts by comparing the demographic characteristics of drug court referrals to drug court admissions, and admissions to exits.