Objectives: The quality of the relationship between people with dementia and their informal caregiver maybe an important determinant of life satisfaction and well-being for both members of the dyad. Taking a dyadic perspective, the aim of this study was to examine whether self- and partner-rated relationship quality influences life satisfaction and well-being for both people with dementia and their caregivers. Design and methods: Using data from 1283 dyads in the Improving the Experience of Dementia and Enhancing Active Life (IDEAL) cohort, we examined the impact of current relationship quality on life satisfaction and well-being in dementia caregiving dyads. Data were analysed using the Actor-Partner Interdependence Model (APIM) framework. Results: Self-rated relationship quality was associated with own life satisfaction and well-being for both people with dementia and caregivers. Partner-rated relationship quality did not influence own life satisfaction or well-being for either member of the dyad. Conclusion: This study is the first to use the APIM framework to explore the dyadic associations between relationship quality and life satisfaction and well-being in a large cohort of dementia caregiving dyads. The obtained findings suggest that the individual perception of the quality of the caregiving relationship held by each member of the caregiving dyad is an important factor for that member's life satisfaction and well-being, while the partner's perception of relationship quality is not. The findings highlight the importance of considering the individual perspective of both the person with dementia and the caregiver and enabling each to maintain positive perceptions of relationship quality.