The Conners 4 meets test standards for psychometric evidence of fairness (AERA, APA, & NCME, 2014). Measurement invariance, differential test functioning, and mean differences for the Conners 4 were examined for key demographic groups (i.e., gender, race/ethnicity, parental education level, and country of residence). While the demographic characteristics explored were extensive, there was a practical limitation to addressing diversity beyond what can be explored with the current samples (e.g., countries of residence other than U.S. and Canada, representation of non-binary gender identities, representation of other racial/ethnic groups). The Conners 4 Content Scales, Impairment & Functional Outcome Scales, DSM Symptom Scales, and Critical & Indicator Items were investigated with respect to the available demographic groups. Statistically significant results were not found for the overwhelming majority of analyses conducted, and very small effect sizes were observed across the rater forms. While teacher ratings may yield slightly higher scores for Black students than White students, the differences were small and are not brought on by item or test bias. There was strong evidence to support the lack of measurement bias and the minimal impact of demographic characteristics on the Conners 4, supporting the fair interpretation of the test scores for youth from diverse backgrounds.