Motivated by attachment theory and recent conceptualizations of perceived partner responsiveness as a core feature of close relationships, the authors examined change in hedonic and eudaimonic well-being over a decade in a sample of more than 2,000 married adults across the United States. Longitudinal analyses revealed that perceived partner responsivenessthe extent to which individuals believe that their partner cares for, appreciates, and understands thempredicted increases in eudaimonic well-being a decade later. These results remained after controlling for initial hedonic and eudaimonic well-being, age, gender, extraversion, neuroticism, and perceived responsiveness of family and friends. Affective reactivity, measured via an 8-day diary protocol in a subset of the sample, partially mediated this longitudinal association. After controlling for covariates, perceived partner responsiveness did not prospectively predict hedonic well-being. These findings are the first to document the long-term benefits of perceived partner responsiveness on eudaimonic well-being.