["Journal of Intellectual Disability Research, EarlyView. ", "\nABSTRACT\n\nBackground\nAs increasing numbers of individuals with intellectual and developmental disabilities (IDD) live into adulthood, they struggle to access high‐quality, age‐appropriate healthcare. Physicians who feel ill‐prepared to care for adults with IDD contribute to worsened access to and quality of care, which can ultimately lead to poorer health outcomes for this population.\n\n\nObjective\nInvestigate physician‐in‐training perceptions of, experiences with and needs for treating patients with IDD.\n\n\nMethods\nWe conducted qualitative, semistructured interviews with 20 senior resident physicians from five residency programs affiliated with the University of Colorado. We analysed data using thematic content analysis to identify and develop overarching themes.\n\n\nResults\nFour major themes emerged using thematic content analysis. First, communication challenges decreased resident confidence in the quality of care they provide. Second, residents felt that they did not have adequate skills to treat patients with IDD. Third, residents felt that this population of adults is not within the purview of most of their practice specialties. Lastly, physicians‐in‐training felt that more exposure to and support in caring for patients with IDD would increase their comfort treating patients with IDD.\n\n\nConclusion\nResidents in adult specialties felt ill‐equipped to care for adults with IDD and limited experiences heightened their fear of making mistakes. Greater experiential learning and better support resources could improve their confidence and future care quality for this important population.\n\n"]