The aim of this study was to explore periodontal health among intellectually disabled individuals living in an institutional rehabilitation centre in the Al-Baha Region of Saudi Arabia. A cross-sectional study was conducted from November 2023 to January 2024. Clinical oral examinations were carried out using the World Health Organization criteria for bleeding sites and the presence of periodontal pockets. Simplified oral hygiene and community periodontal indices were employed to evaluate participants’ oral health. A total of 89 participants, comprising both males and females with intellectual disabilities, were included in this study. Gender, severity of intellectual disability, type of additional physical disability, tooth brushing habits and oral hygiene status were significantly associated with the presence of periodontal disease. Additionally, poor oral hygiene, not brushing teeth and periodontal pockets of 4–5 mm and 6 mm or more were significantly more prevalent among individuals with severe and moderate intellectual disabilities (p = 0.001, p = 0.001, p = 0.001 and p = 0.001, respectively). The prevalence of periodontal disease among the studied population was 54%. The odds of having periodontal disease were significantly higher in the severe intellectual disability group compared to the mild intellectual disability group (OR = 2.328, 95% CI = 1.430–3.631, p = 0.03). It was also found that intellectually disabled participants with additional physical disabilities suffered more from periodontal disease than those without additional physical disabilities (OR = 0.971, 95% CI = 0.235–4.023, p = 0.025). Overall, individuals with intellectual disabilities had a significant demand for periodontal care. This study highlighted the need for more organised preventive programmes for individuals with intellectual disabilities. Dentists should be vigilant about improving periodontal health, focus on preventive programmes and provide comprehensive dental care with an emphasis on periodic recall and monitoring.