Social service professionals are more frequently identifying children who witness adult domestic violence as victims of that abuse. This article expands common definitions of how children witness violence, and adult domestic violence in particular. Over 80 research papers were reviewed and a variety of behavioral, emotional, cognitive and physical functioning problems among children were found to be associated with exposure to domestic violence. Factors that appear to mediate the impact of witnessing violence, such as child gender, age, and time since last exposure to violence are identified. Concerns about research methodology are also raised.