Introduction People with intellectual and developmental disabilities under the United Nations Convention on the Rights of Persons with Disabilities (UNCRPD) have the right to access sexual health services including information, education, and support. Little is known about the capacity of sexual health professionals to provide these services. Methods Using an observational research design, this study utilised a descriptive survey tool (PASH–Ext) that also encompassed a standardised measure, with a cross-sectional purposive sample of 52 Australian sexual health professionals. Data was collected in 2020. Results Just over half of the participants reported having received training in their preservice education to work with people with intellectual and developmental disabilities, of these 60% held the view that people with intellectual and developmental disabilities would not feel embarrassed receiving sexual health information and support. Conclusion The study found that training is both important to the professionals’ preparedness to work with people with intellectual and developmental disabilities, and that these professionals advocate for the continuation of this training in pre-service courses and additional training in post service education for sexual health workers. Policy Implications To progressively realise Article 25 of the UNCRPD signatory, countries need to ensure sexual health services are accessible to people with intellectual and developmental disabilities. This study recommends that sexual health policy addresses equity of access for people with intellectual and developmental disability by ensuring all staff are prepared and supported to provide these services.