This study examined the effects of adverse childhood experiences (ACE)s on Head Start eligible low-income children’s developmental outcomes based on the Head Start Impact Study data (n = 4442). The ACEs consisted of parental alcohol/drug use, parental depression, neglectful parenting practices, family violence, and household risk factors. Children’s developmental outcomes were cognitive, socio-emotional, and health outcomes. The following questions were explored: (a) Do ACEs have an impact on children’s cognitive, social, and health outcomes? (b) Does the Head Start program have any impact on the effects between ACEs and children’s cognitive, social and health outcomes? (author abstract)