In recent years, families with children from the Northern Triangle countries of Central America constitute a large and growing proportion of migrants and overall filed asylum claims. In an effort to deter overall immigration through the U.S.-Mexico border, the executive branch under the Trump administration has made substantial changes to federal immigration and asylum policy in recent years. Given the sensitive nature of early development and the hardship and trauma that many migrant children have experienced, immigration policies that do not prioritize child wellbeing, and in fact, neglect or harm it, can have lifelong negative consequences on physical and psychological wellbeing. In light of the scope of children and families affected by these policies and potential magnitude of their effects, the present review aimed to: (1) outline federal immigration policies under the Trump administration that primarily impacted migrant children and families; (2) review the research base regarding the effects of these policies on physical safety and health, development, mental health, family wellbeing, and education; and (3) provide policy recommendations to prevent further harm, mitigate the great harm already done, and prioritize child wellness moving forward. Findings from the review indicate that even short experiences of detention, particularly when children are separated from parents and caregivers, are associated with serious, lasting negative effects across every domain of functioning. The practices of separation, detention, and removal to temporary encampments compound traumatic experiences that migrant families are often fleeing, which in turn may set up already vulnerable children for a trajectory of continued marginalization. Future directions for research and implications for policy and practice are discussed.