This brief report describes results from an efficacy test of Adolescent ParentWays program, an intervention developed for parents of adolescents ages 13–16 years who have symptoms of behavioral problems and social difficulties. Families were assigned to one of three groups. The in-person treatment group included parents who attended a 10 week, multiple session intervention program (n = 26), an online only treatment group (n = 29) that was given access to a web-based version of the program, or a wait-listed control group (n = 22). Pre- and post- testing of parents and their adolescent child was conducted. The Adolescent ParentWays intervention program was associated with several significant pre-post differences, including enhanced parent–adolescent relationship quality, increased parent knowledge and monitoring, and lower perceived stress for parents. Significant differences in the outcome variables were found for the in-person treatment group and for the on-line only versions of the program, versus a wait-listed control group. This demonstrates the effectiveness of the Adolescent ParentWays intervention program. The findings support the important role of parents in shaping adolescent behaviors and the positive impact of parenting training programs—both in-person traditional models and well as online versions—in promoting positive parent–adolescent relationships. The merits of using online parent training programs are discussed.