Objective To examine the risk of emotional and behavioral problems among children with a chronic physical illness. Methods Random-effects meta-analysis was computed to integrate the results of 569 studies that used the Child Behavior Checklist, Youth Self Report, and the Teacher Report Form. Results Young people with a chronic physical illness have higher levels of internalizing (g = .47 standard mean difference), externalizing (g = .22) and total behavior problems (g = .42) than healthy peers. The largest differences were found in parental ratings and the weakest differences in adolescent self-ratings. Strongest elevations of internalizing problems were found for chronic fatigue syndrome and strongest elevations of externalizing problems were observed for epilepsy and migraine/tension-type headache. Effects also varied by country and, in part, by age, gender, year of publication, and study design. Conclusions The results call for regular screens for psychological distress and referrals for mental health services, when needed.