In this article, we explore a largely uncharted field of research—how a partner’s life satisfaction is associated with one’s own life satisfaction among older (50+) couples in Europe. We also study the moderating role of caregiving, health difference, social relations, and country of residence. We analyse longitudinal data from seven waves of the Survey of Health, Ageing and Retirement in Europe using fixed effects regression techniques. Our analysis sample includes 155,494 observations (49,520 individuals in 24,760 couples). Our results show that the association between the life satisfaction of each partner was relatively strong, even after controlling for both partners’ health, demographic, and socioeconomic factors. This association was further moderated by caregiving roles, health disparities, social networks, and the broader national context. For example, the association was weaker when only one partner provides care or when only one faces health issues. Among women, the association between their life satisfaction and their partner's was pronounced when the social network was limited. Furthermore, while most couples report similar levels of life satisfaction, more than a third of individuals differ from their partner. These findings highlight the interconnected nature of well-being in later life and suggest that policies aimed at improving individual life satisfaction may have broader benefits when they take the dyadic context into account. Our study contributes to a growing body of evidence on within-family well-being spillovers and emphasize that the strong association between partners’ life satisfaction could be better taken into account in social and health policies as well as research on well-being.