Understanding disparities in young children’s behavior is crucial because both theoretical perspectives and empirical research suggest that behavior in early childhood is linked to divergent trajectories throughout the life course (Caspi, Bem, & Elder, 1989; Entwisle & Alexander, 1989; Hofstra, Van der Ende, & Verhulst, 2000; McLeod & Kaiser, 2004). Advantages and disadvantages accumulate over time; children who fall behind their counterparts in early childhood are at risk for disadvantaged outcomes in later childhood, adolescence, and adulthood. As described in this chapter, we used data from the Early Childhood Longitudinal Study—Kindergarten Cohort (ECLS-K) to examine variation in both parent- and teacher-reported behavioral outcomes by race and immigrant status. We explored the immigrant paradox in two ways. First, we compared outcomes of minority immigrant children with those of their native-born White counterparts. Second, we compared outcomes of minority immigrant children with those of native-born children of the same race. Additionally, when multivariate analyses provided evidence of an immigrant paradox, we examined the extent to which characteristics of the family environment— including family structure, cultural interactions between parents and children, and speaking a non-English language at home—may explain the advantages experienced by immigrant children. Our focus on behavioral outcomes allowed us to bypass one limitation of examining academic achievement among immigrant children with the ECLS-K. In these data, some language-minority children were excluded from the academic readiness assessments. In kindergarten, about 15% of the sample took the Oral Language Development Scale test, and about half of those tested (41% of the children who spoke Spanish and 62% of the children who spoke another language) had inadequate English skills to take the assessments in English (Rock & Pollack, 2002). All parents and teachers, regardless of children’s language minority status, were asked about children’s behavior.