This study examined the efficacy of a program for parents of young adolescents combining behavioral family intervention with acceptance-based strategies. 180 parents were randomly allocated to a 6-session group ABCD Parenting Young Adolescent Program or wait-list condition. Completer analysis indicated parents in the intervention reported significantly higher adolescent prosocial behaviors (p = 0.020), lower conduct problems (p = 0.048) and total difficulties (p = 0.041). These parents also reported lower stress associated with adolescent moodiness (p = 0.032), parent life-restriction (p less than 0.001), adult-relations (p less than 0.001), social isolation (p = 0.012), incompetence/guilt (p less than 0.001), lower stress in the parenting domain (p less than 0.001) and lower overall stress (p = 0.003) relative to the control condition following the intervention period. No other statistically significant differences were evident (p less than 0.05). Results of intention-to-treat analyses were similar. Greater reliable clinically significant change was also achieved for the intervention condition. Participants reported high satisfaction with all elements of the ABCD program. Results suggest the program may assist parents of young adolescents to promote or maintain protective factors in their families. Australian and New Zealand Clinical Trials Registry: ANZCTRN12609000194268. (Contains 4 tables and 1 figure.)