Autism spectrum disorders (ASDs) are developmental disabilities that affect an estimated 1 in 110 children in the U.S. However, there are few programs available to families as children move into adulthood, even though the stresses of parenting a child with ASD persist. The paucity of evidenced-based programming during this transition period is especially concerning given that adolescence is a time of notably high stress for families. This study addresses this gap by evaluating an intervention program for families prior to the transition out of high school. Past research has demonstrated that family psychoeducation programs can reduce high levels of emotional intensity in the family, known as expressed emotion (EE), and that this leads to reduced family stress and better outcomes for individuals with mental health conditions; however, no studies have attempted to evaluate this type of program for families of individuals with ASD. This study will test a family psychoeducation intervention, Transitioning Together, which the researchers have recently adapted for use with families of adolescents with ASD. The Transitioning Together program includes (a) individual family sessions, (b) multi-family group sessions for parents, and (b) social group sessions for adolescents. Families are also regularly provided with individualized resources and referrals. The study will randomly assign 48 families of adolescents (aged 14-21) with ASD to one of two conditions: (1) initial intervention group or (2) waitlist control group. Parent variables (stress, well-being, and salivary cortisol), family variables (expressed emotion and empowerment), and adolescent variables (behavior problems, symptoms, and community involvement) will be assessed before and after the intervention. Variables related to feasibility and acceptability of the intervention will also be measured. The researchers hypothesize that families in the initial intervention group will display greater improvements in parental stress, family EE and empowerment, and adolescent behavior and community involvement compared to families in the waitlist control. This study has the potential to enhance the lives of adolescents with ASD by reducing levels of distress within the family system and improving family coping strategies. Findings are expected to lay the groundwork necessary to seek support for a randomized control trial of the intervention in a community setting.