Objective Family caregivers of people with dementia often report high levels of stress and depression, but little is known about those who contemplate suicide or self‐harm. This study explores thoughts of suicide, self‐harm and death in dementia caregivers and investigates the characteristics that distinguish them from those without such thoughts. Methods Data were collected every 3 months, for 24 months, from 192 family caregivers of people with dementia living in the Netherlands. Caregivers did not have a clinical depression or anxiety disorder at baseline. Suicide‐related thoughts were measured with an item from the Mini International Neuropsychiatric Interview, a diagnostic instrument for DSM‐IV mental disorders. Fisher exact, analysis of variance or Kruskal–Wallis tests compared the characteristics of caregivers who had contemplated suicide with two comparison groups. Results Within 24 months, 76 caregivers reported symptoms of a potential depression and were further assessed for suicidal thoughts. Nine carers (11.8%, 4.7% of the total sample) reported suicidal thoughts with three of those at multiple points. Caregivers with suicidal thoughts had more severe depressive and anxious symptoms, had a lower sense of competence and mastery, felt less happy and experienced more health problems, less family support and more feelings of loneliness than caregivers who had not. Conclusion Suicidal thoughts are present in dementia caregivers and can persist across the care trajectory. Various psychological and social characteristics significantly distinguish caregivers with suicidal thoughts from those without. More research is needed to enable the identification of high‐risk caregivers and provide an evidence base for the development of preventive strategies and interventions. © 2017 The Authors. International Journal of Geriatric Psychiatry Published by John Wiley & Sons Ltd.