This study investigates factors associated with the person with dementia and the caregiver to identify those associated with an increased risk of transition to a care home. IDEAL data were collected at baseline and at 12- and 24-month follow-up for 1545 people with dementia and 1305 caregivers. Modified Poisson regressions with an offset for 'person years at risk' were used. Person with dementia factors explored were personal characteristics, cognition, health, self- and informant-rated functional ability, and neuropsychiatric symptoms. Caregiver factors explored were personal characteristics, stress, health, and quality of the dyadic relationship. A 5% people moved into care. Risk of moving into a care home was higher among people with dementia who were ≥80 years, among people with Parkinson's disease dementia or dementia with Lewy bodies, and among those without a spousal caregiver. Poorer cognition and more self-rated or informant-rated functional difficulties increased the risk of moving into care. Factors related to increased dementia severity and greater disability are the primary influences that place people with dementia at greater risk of moving into a care home. Strategies that help to maintain everyday functional ability for people with dementia could help delay people with dementia moving into care.