Objectives: Illness representations shape responses to illness experienced by the self or by others. The illness representations held by family members of those with long-term conditions such as dementia influence their understanding of what is happening to the person and how they respond and provide support. The aim of this study is to explore components of illness representations (label, cause, control and timeline) in caregivers of people with dementia. Method: This was an exploratory study; the data reported came from the Memory Impairment and Dementia Awareness Study (MIDAS). Data from semi-structured interviews with 50 caregivers of people with dementia were analysed using content analysis. Results: The majority of caregivers gave accounts that appeared to endorse a medical/diagnostic label, although many used different terms interchangeably. Caregivers differentiated between direct causes and contributory factors, but the predominant explanation was that dementia had a biological cause. Other perceived causes were hereditary factors, ageing, lifestyle, life events and environmental factors. A limited number of caregivers were able to identify things that people with dementia could do to help manage the condition, while others thought nothing could be done. There were varying views about the efficacy of medication. In terms of timeline, there was considerable uncertainty about how dementia would progress over time. Conclusion: The extent of uncertainty about the cause, timeline and controllability of dementia indicated that caregivers need information on these areas. Tailored information and support taking account of caregivers' existing representations may be most beneficial.