This study examined social-emotional functioning in children with Gilles de la Tourette's syndrome (TS) alone and children with TS and Attention Deficit Hyperactivity Disorder (ADHD). In addition, the contribution of family functioning to social competence was examined. Children with a clinical diagnosis of TS were recruited from the Yale Child Study Center TS specialty clinic. Unaffected control children were recruited through newspaper advertisements and announcements within the university and at area schools. The final sample consisted of 72 children (45 boys and 27 girls) between the ages of 8 and 14. Sixteen children met DMS-III-R criteria for TS, 33 children met criteria for TS and ADHD, and 23 children had no psychiatric diagnoses. Children with TS and ADHD evidenced more externalizing and internalizing behavior problems and poorer social adaptation than children with TS only or unaffected controls. Children with TS only were not significantly different from unaffected controls on most measures of externalizing behaviors and social adaptation but did exhibit more internalizing symptoms. Tic symptom severity was not associated with social, behavioral, or emotional functioning among children with TS, even after stratifying by medication status. However, ADHD diagnosis, obsessional symptom severity, and family functioning were significantly associated with social and emotional adjustment among TS children. Moreover, family functioning was associated with social and emotional adjustment even after controlling for TS and ADHD diagnostic status. These findings demonstrate that much of the social and behavioral dysfunction in children with TS is ADHD-specific and children with TS alone have a very different social-emotional profile than do those with TS plus ADHD. Finally, social-emotional adjustment in children with TS is best understood within the family context.