["Journal of Applied Research in Intellectual Disabilities, Volume 39, Issue 3, May 2026. ", "\nABSTRACT\n\nAbstract\n\n\nBackground\nWhile COVID‐19 had a devastating impact on mental health worldwide, little is known about its effects on adults with intellectual and developmental disabilities. We used a community‐based participatory approach to study this population's mental health experiences.\n\n\nMethods\nSix focus groups were conducted: four with adults with intellectual and developmental disabilities (n = 21) and two with caregivers (n = 13). Conventional content analysis and thematic network analysis were utilised.\n\n\nResults\nWe identified cascading impacts of the pandemic on the mental health of this population. Sub‐themes included: (1) environmental effects, (2) emotional effects and (3) physical and behavioural effects of COVID‐19. Five modifying factors were identified.\n\n\nConclusions\nThe COVID‐19 pandemic, while specific in its restrictions and timing, illustrated and exacerbated unmet mental health needs of adults with intellectual and developmental disabilities. These results suggest opportunities for empirical research and policy development, relevant for future emergencies and ongoing medical and non‐medical support of this population.\n\n"]