Attention Deficit Hyperactivity Disorder (ADHD) in children is associated with hyperactivity and impulsitivity, attention problems, and difficulties with social interactions. Pharmacological treatment may alleviate symptoms of ADHD but seldom solves difficulties with social interactions. Social skills training may benefit ADHD children in their social interactions. We examined the effects of social skills training on children's social competences, general behaviour, ADHD symptoms, and performance in school. To assess the effects of social skills training in children and adolescents with ADHD. We searched the following electronic databases: CENTRAL (2011, Issue1), MEDLINE (1948 to March 2011), EMBASE (1980 to March 2011), ERIC (1966 to March 2011 ), AMED (1985 to June 2011), PsycINFO (1806 to March 2011), CINAHL (1980 to March 2011), and Sociological Abstracts (1952 to March 2011). We also searched the metaRegister of Controlled Trials on 15 October 2010. We did not apply any language or date restrictions to the searches. We searched online conference abstracts and contacted 176 experts in the field for possible information about unpublished or ongoing RCTs. Randomised trials investigating social skills training for children with ADHD as a stand alone treatment or as an adjunct to pharmacological treatment. We conducted the review according to the Cochrane Handbook for Systematic Reviews of Intervention. Two authors (OJS, MS) extracted data independently using an appropriate data collection form. We performed the analyses using Review Manager 5 software. We included 11 randomised trials described in 26 records (all full text articles) in the review. The trials included a total of 747 participants. All participants were between five and 12 years of age. No trials assessed adolescents. In 10 of the trials the participants suffered from different comorbidities.The duration of the interventions ranged from eight to 10 weeks (eight trials) up to two years. The types of social skills interventions were named social skills training, cognitive behavioural intervention, multimodal behavioural/psychosocial therapy, behavioural therapy/treatment, behavioural and social skills treatment, and psychosocial treatment. The content of the social skills interventionswere comparable and based on a cognitive behavioural model.Most of the trials compared child social skills training and parent training plus medication versus medication alone. Some of the experimental interventions also included teacher consultations.More than half of the trials were at high risk of bias regarding generation of the allocation sequence and allocation concealment. No trial reported blinding of participants and personnel and most of the trials had no reports regarding differences between groups in collateral medication for comorbid disorders. Overall, the trials had high risk of bias due to systematic errors. Even so, as recommended by the Cochrane Handbook of Systematic Reviews of Interventions, weused all eligible trials in the meta-analysis, but the results aredowngraded to low quality evidence.There were no statistically significant treatment effects either on social skills competences (positive value = better for the intervention group)(SMD 0.16; 95% CI -0.04 to 0.36; 5 trials, n = 392), on the teacher-rated general behaviour (negative value = better for the intervention group) (SMD 0.00; 95% CI -0.21 to 0.21; 3 trials, n = 358), or on the ADHD symptoms (negative value = better for the intervention group) (SMD -0.02; 95% CI -0.19 to 0.16; 6 trials, n = 515).No serious or non-serious adverse events were reported. The review suggests that there is little evidence to support or refute social skills training for adolescents with ADHD. There is need for more trials, with low risk of bias and with a sufficient number of participants, investigating the efficacy of social skills training versus no training for both children and adolescents.