Introduction: The Intellectual and Developmental Disability Mental Health (IDD-MH) Research Partnership was created to learn about the experiences and needs of young adults with IDD-MH while accessing and using mental health services. Our national partnership consists of six young adults, five professionals, researchers at Boston University, and representatives from Self Advocates Becoming Empowered and The Arc of the United States. Our partnership worked together virtually for one year. Methods: We designed and conducted a web survey with young adults with IDD-MH ages 18-30 living in the United States (n = 76). We also completed four national storytelling sessions (1 in person, 3 virtual) that included young adults with IDD-MH (n = 10) and parents of young adults with IDD-MH (n = 6). Results: We identified eight priority topic areas for young adults with IDD-MH: Transition to Adulthood, Insurance & Financial Resources, Professionals' Competence, Understanding the Experiences of People who Communicate Differently, Hospitalization, Medication, Alternatives to Medication, and Social Supports. Conclusions: Using what we learned, we generated recommendations to advance research and practice in areas important to young adults with IDD-MH. These recommendations highlight the importance of community-based options, choice, autonomy, and control for young adults with IDD-MH.