The relationship between social support and adjustment was investigated in children with a chronic physical illness or handicap. Mothers of 153 children with juvenile diabetes, juvenile rheumatoid arthritis, chronic obesity, spina bifida, or cerebral palsy reported on these children's family support, peer support, externalizing behavior problems, and internalizing behavior problems. Children reported as having high social support from both family and peers showed a significantly better adjustment than those with high social support from only one of these sources. Chronically ill or physically handicapped children without high support from both family and peers were reported to have significantly more behavior problems than children in general. Both family and peer support contributed negatively and independently to the variance in externalizing behavior problems, whereas only peer support did so for internalizing behavior problems. There were no interactions between type of support and either sex or age in predicting adjustment.