This review summarizes studies investigating psychophysiological alterations associated with pediatric posttraumatic stress disorder (PTSD). The authors conducted a computer-based search in the databases PsycINFO, PSYNDEXplus, and Medline. Additional studies were retrieved using a pyramid scheme. The literature search identified 29 articles. Most studies measured alterations shortly after exposure. Differences from controls emerged mainly in the sympathoadrenal system and the hypothalamic–pituitary–adrenal axis. Elevated acute heart rate immediately after traumatization was associated with increased risk for PTSD. The literature on psychophysiological characteristics of pediatric PTSD is relatively small and diverse. Nevertheless, findings indicate exaggerated baseline activation across various measures. Studies examining the course and reversibility of psychophysiological alterations are lacking.