Self-determination and self-advocacy are critical skills for students with disabilities (SWD). Around the world, practitioners and educators express concerns that students transitioning from school to post-high school settings often lack the awareness to discuss their strengths, preferences, and needs. To improve self-determination, a one-year randomized controlled trial design was utilized with high school students with high incidence disabilities (n = 198). These students matched on key variables before being randomly assigned to their respective groups. Both treatment and control groups received regular tiered transition services, activities, and support while the control group also received the Ask.Explore.Connect self-determination instruction and intervention. Results demonstrate that discussions are an effective practice to increase student self-determination. Treatment students had greater increases in self-determination than the control group across all disability categories and service levels. Benefits of the tool and intervention allowed for increased self-advocacy, self-determination, choice-making and social skills, field testing of evidence-based best practices, and use of authentic settings.