Background: We investigated the prevalence of swallowing difficulties and associated factors in people with intellectual disability. Methods: We included people aged 50+ receiving care for people with intellectual disabilities. The Dysphagia Disorder Survey (DDS) was used to assess swallowing difficulties. We determined the agreement between the DDS and swallowing difficulties in medical records. We used logistic regression analyses to explore associated factors. Results: One thousand and fifty people were included. The prevalence of swallowing difficulties was 43.8%. Swallowing difficulties were not reported in the medical records of 83.3% of these cases. Frailty (odds ratio (OR) = 4.22, 95% CI = 2.05-8.71), mobility impairment (OR = 2.50, 95% CI = 1.01-6.19), and mealtime dependency (OR = 3.05, 95% CI = 1.10-8.47) were independently associated with swallowing difficulties. Conclusion: Swallowing difficulties are prevalent in older people with intellectual disability but may be under-recognised. Frailty may be a good indicator for population-based screening for swallowing difficulties.