This dissertation examines the heterogeneity among immigrant children in the United States. Given the global demand for female labor from developing countries, that many of these families are poor and cannot afford to migrate together, and that once separated reunification is further prolonged by immigration policies, many immigrant children are separated from a primary caregiver for some portion of their development. This dissertation project compares the developmental outcomes of three groups of Caribbean immigrant children, one group of first-generation children who migrated with their mothers (family migration), another group of first-generation children who were separated from their mothers due to migration (separated migration), and a third group of second-generation children. Studying maternal separation in immigration illuminates an important context in which child development occurs for some immigrant children. Drawing support from the research on adverse childhood experiences, like childhood poverty, it is hypothesized that different immigration ecologies will engender different parent-child relations, mental health outcomes, and cognitive abilities. Chapter two examines the attachment patterns of Caribbean immigrant adolescents and establishes a link between maternal separation in immigration and attachment anxiety. Chapter three explores the role of attachment security and parenting styles on the mental health of Caribbean immigrant youth. The results of this paper show that attachment security fully mediates the link between immigration experiences and mental health outcomes. Chapter four proposes executive function as a potential explanatory variable for the academic disparities observed among immigrant youth. Results show that children from the family migration group report better cognitive flexibility than the other two groups. Results also show that parental involvement positively and significantly impacts executive function abilities. Together, this dissertation provides evidence that maternal separation due to immigration is associated with some adverse child development outcomes. The findings from this project are useful to families, educators, and policy-makers as work together to support this population.