Background The input of youth with intellectual disabilities in health promotion and health disparities research is essential for understanding their needs and preferences. Regular physical activity (PA) is vital for health and well‐being, but levels are low in youth generally, including those with intellectual disabilities. Understanding the perceptions of and barriers to PA as reported by youth with intellectual disabilities themselves is important for designing effective interventions. Materials and methods We developed a structured interview that queried youth with intellectual disabilities and typically developing youth (ages 13–21 years) about their enjoyment, preferences and perceived barriers to PA. We describe the development of this interview and present its test–retest reliability on 15 youth with intellectual disabilities and 20 typically developing youth. Results Twenty‐three of 33 questions were reliable in both groups. The results suggest that youth with intellectual disabilities can reliably report activities that they do or do not enjoy, as well as their beliefs and perceived benefits of PA. Conclusions Self‐reported information on the experiences, preferences, beliefs and perceptions about among youth with intellectual disabilities is key for research efforts in health promotion and health disparities.