It is known that the oral health status of people with intellectual disabilities (IDs) is likely to be compromised as compared with the general population. Until recently, the trend of oral hygiene among the adult population with intellectual disabilities in Brunei Darussalam had yet to be studied. Thus, the aim of this study was to determine the oral hygiene practices, oral health knowledge and dental appointment patterns among the adult population with IDs in Brunei Darussalam. A cross-sectional study was conducted at different service providers in Brunei Darussalam for adults with IDs. An easy-to-read questionnaire was distributed to the participants. The responses of the questionnaire for IDs were analyzed. A total of 34 participants were recruited. It was found that all participants were practicing their daily oral hygiene routine. In terms of dental visits, more than half visit the dentist at least once a year. The majority of the participants agreed that visiting the dentist every 6 months was essential. This study showed that adults with IDs in Brunei Darussalam were aware of the importance of oral health and were maintaining their daily oral hygiene, although not with the ideal method. It is important for clinicians to not only educate the individuals with IDs but also their carer(s) when it comes to oral health knowledge, as carers play a key role in the oral health of the people under their care.