The notion that development influences children's responses to traumatic stress is not novel. Chronological age and maturity level interact with environmental factors to mediate responses to trauma. Clinicians and researchers have confirmed that children can experience the full range of traumatic stress reactions seen in adults, and many youth meet criteria for DSM-IV diagnoses of either acute stress disorder or posttraumatic stress disorder (PTSD). However, many types of childhood trauma including psychological maltreatment, neglect, separation from caregivers, and inappropriate sexual contact are not fully accounted for by these disorders. Even when children experience events that are more commonly characterized as traumas, research indicates that their reactions are not fully congruent with the criteria provided in the DSM-IV, suggesting that these criteria may not adequately describe trauma responses in the pediatric population. Services and treatment for trauma are often conceptualized as interventions after the fact, rather than proactive measures. While reactive interventions are clearly valuable, there are multiple opportunities for school psychologists to implement prevention-based practices that will address the needs of young children who have experienced trauma. In this article, the author discusses how to understand and address early childhood trauma.