Children of immigrants come from diverse backgrounds and enter school with different family migration experiences and resources. This paper addresses two basic questions: (1) to what extent does generation status exert an independent effect on early school performance net of race/panethnicity, language proficiency, and the family resources available to children as they enter formal schooling? and (2) to what extent do these broad conceptualizations of children in immigrant families mask variation by national origins? We take advantage of longitudinal data on a kindergarten cohort from the Early Childhood Longitudinal Study to examine children from diverse backgrounds. Considerable variation in academic performance persists across racial/panethnic groups as well as by country-of-origin background and linguistic ability even when adjusting for family background, resources, and previous academic performance. We find some intriguing evidence of early “segmentation” among children from various groups, suggesting some convergence within race and ethnicity for some children. However, this conclusion should not be overstated, because the results also point to the great diversity by national origins that are masked by reliance on racial/panethnic groupings.