To the best of our knowledge, this study is the first to simultaneously examine SES-related differences in EF, self-regulation skills, and behaviors using multi-method, multi-informant approaches. We employ rich multi-method, multi-informant data to quantify the SES gradient in social and emotional skills and behaviors in the two years prior to kindergarten entry. The data contains information about children’s EF (as measured with direct assessment), self-regulation skills (as reported by trained examiners, parents, and early education and care educators), and behaviors (as reported by parents and educators), making it possible to provide a comprehensive description of early disparities in a variety of foundational social and emotional skills. (author abstract)