Family functioning has long been a focus of research in psychopathology. Decades of research has shown that family factors are associated with symptom severity, relapse, functional outcomes, and conversion to psychosis among at-risk individuals. Previous studies suggest family functioning varies across cultures, which raises the possibility that associations between family factors and psychopathology may also differ by culture. Furthermore, family functioning assessment generally involves instruments that have not been systematically validated for use with individuals from diverse cultural backgrounds. The current study used data from the Adolescent Brain Cognitive Development study (N = 11,138) to: (1) evaluate three family functioning scales (i.e., Family Environment Scale, Child's Report of Parental Behavior Inventory, Parental Monitoring Survey) and the Prodromal Questionnaire – Brief Child version for measurement invariance across racial/ethnic groups; (2) investigate the relations between family factors and psychosis; and (3) compare relations derived from Step 2 between racial/ethnic groups. Full scalar invariance was tenable for the CRPBI and the PQ-BC, providing statistical support for mean comparisons across groups. The FES and the PMQ lacked scalar invariance, which suggests mean comparisons across groups may not be appropriate. The CRPBI and the PMQ are significantly associated with the PQ-BC, and all three family scales had equivalent relations with the PQ-BC across groups. The current study highlights the importance of evaluating assessment instruments for measurement invariance across racial/ethnic groups. Results also help to connect specific family factors to the etiology of psychotic disorders among US children and adolescents.