AimsTo investigate experiences and expectations of parents/siblings of adults with Down Syndrome (DS) regarding oral healthcare, and explore factors impacting on access and experience of dental care for this group. Design A two phase qualitative and quantitative study using in-depth interviews with a convenience sample of six parents/siblings, and a postal questionnaire of 200 parents/siblings of adults with DS who are members of the Down Syndrome Association. Results The main themes elicited from the qualitative interviews related to concern, experiences, parents'/siblings' attitudes, preferences and information. The response rate from the postal questionnaire was 63.5%. Adults with DS attended the dentist regularly but received little restorative treatment. Experience of oral healthcare was influenced by the attitudes and skills of dental health professionals; stigma; and relatives' expectations of dentists, their oral health beliefs, information and support received, knowledge and priorities. Parents/siblings wanted dentists to be proactive in providing more information on oral health issues in collaboration with other health and social care professionals. Conclusions Whilst most adults with DS visited the dentist regularly, relatively little treatment had been provided. Parents highlighted a need for appropriate and timely oral health information early in their child's life, and access to dentists who were sympathetic, good communicators and well-informed about DS.