Background: Individuals with intellectual disability or autism exhibit suicidal behaviours at an equal or greater rate than the general population, yet little is known about associated risk factors. This study explores suicidality in these populations, focusing on their understanding of suicide and death and perceptions of their direct support staff regarding their suicidality. Method: Semi-structured interviews from 23 suicidal and non-suicidal participants and their support staff were analysed qualitatively to extract common themes and compare between groups. Results: A breadth of suicidal behaviours was documented. Generally, suicidal participants demonstrated a more elaborate understanding of suicide and death than non-suicidal participants. While staff often acknowledged never having discussed the topic with their client, most assumed they understood death accurately. Conclusion: Results suggest interactions between conceptions of death and suicidal behaviour and a need for discussion around death and suicide in clinical settings. Implications for future research and clinical practice are discussed.