Research Findings: At present, few resources are available to researchers, teachers, and practitioners who wish to quickly and reliably assess children's self-regulation within the classroom context, and particularly within settings serving low-income and ethnic minority children. This paper explores the psychometric properties of a teacher-report composite of 2 clinical measures of self-regulation--the Barratt Impulsiveness Scale (version 11; BIS-11) and the Behavior Rating Inventory of Executive Function (BRIEF)--in a sample of low-income African American and Hispanic children. Results of factor analyses revealed a 2-factor solution for the composite measure formed from the BIS-11 and the BRIEF that corresponded to the latent domains of cognitive and behavioral self-regulation. The composite scale was found to have high internal consistency, reliability, and concurrent validity compared to a previously validated measure of teacher-rated inattention and hyperactivity-impulsivity. In addition, results of multigroup comparisons provide evidence for measurement invariance of the composite measure across race, poverty risk status, and gender. Practice or Policy: The results support the usefulness of a teacher-rated combined version of the BIS-11 and the BRIEF for the assessment of low-income, ethnic minority children's cognitive and behavioral self-regulation. This study also helps to inform the theoretical relationship between the cognitive and behavioral subdomains of child self-regulation. (Contains 2 footnotes and 4 tables.)