--- - |2+ Social interaction deficits form a core characteristic of ASD that is commonly targeted through social‐skill groups. The Program for the Education and Enrichment of Relational Skills (PEERS®) is a well‐established parent‐assisted intervention for adolescents, which addresses key areas of social functioning. PEERS® has been mainly studied in North‐America and its evaluations were mostly questionnaire based. The aim of the current study was to test the effectiveness of the adapted and translated Hebrew version of the PEERS® intervention in a randomized controlled trial, using behavioral measures of peer interaction, in addition to self, parent, and teacher reports. Forty‐one participants with ASD and no intellectual impairment, aged 12–17 years, were randomly assigned to an immediate intervention or a delayed‐intervention group. All participants were assessed before and after the immediate intervention, and again at follow up, after the delayed intervention took place. Results revealed intervention‐related behavioral improvements on adolescents’ engagement, question‐asking, and physical arousal. Parental reports indicated improved social skills, and reduced ASD symptoms. Adolescents reported on more social encounters, greater empathy, and scored higher on social‐skill knowledge. Most of these effects maintained at a 16‐week follow‐up. Teacher reports' yielded effects only on pre‐post intervention analysis. Adolescents’ improvement on behavioral engagement predicted parent‐reported social skills improvement. Our findings support the effectiveness of the adapted Hebrew version of PEERS® for adolescents with ASD, through significant behavioral and questionnaire‐based outcomes, which maintained at follow‐up. Autism Res 2018. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. Lay Summary Social‐skills groups, which facilitate key social deficits characteristic of ASD, are a popular intervention for adolescents with ASD. Indeed, many treatment protocols have been published, and some have also been research validated. However, there have been inconsistent findings regarding the effectiveness of different protocols, in addition to limited findings of improvement beyond questionnaire reports. This study evaluated the Hebrew adaptation of the PEERS® intervention, a 16‐weeks long program, which involves the parents as their adolescents’ social coaches. Following the intervention, adolescents improved their social‐skills, participated more in social encounters, reported greater empathy, and demonstrated higher social‐skill knowledge. A live play‐role assessment with an unfamiliar peer indicated that adolescents showed greater involvement, asked more questions and were more physically relaxed during the conversation. Improvements maintained 16 weeks after the intervention was completed. - Autism Research, EarlyView.