Background: There is insufficient evidence to guide decisions around (non-)disclosure of bad news of life-limiting illness and death to people with intellectual disabilities. Aim: The aim of this study was to develop guidelines for decisions about (non-)disclosure of bad news around life-limiting illness and death to people with intellectual disabilities, by examining stakeholders' preferences (and reasons) around disclosure and non-disclosure. Materials and methods: Focus groups and interviews were held with 109 participants: people with intellectual disabilities, family carers, intellectual disabilities professionals and medical healthcare professionals. Results: People with intellectual disabilities had wide-ranging views about disclosure. Reasons for non-disclosure included: preventing distress; too difficult for the bearer of bad news; the bearer of bad news lacks knowledge; inability to understand; no sense of time; conflicting views among stakeholders. Reasons for disclosure included: a right to know; knowledge helps the person cope; need for involvement. Conclusion: Disclosure of bad news could cause harm in some situations, but this needs careful assessment. The authors present guidelines for disclosure that now need to be tested in practice. (Contains 4 figures.)