The current research examined effects of accurate and biased perceptions of romantic partners’ responsive support provision on perceivers’ well-being. Perceivers discussed a personal problem with their romantic partners (“targets”). Perceivers’ perceptions of targets’ responsive support following the discussion were related to external indicators of targets’ behavior, but these perceptions also were predicted by perceivers’ sentiments toward targets, suggesting that processes underlying perceivers’ perceptions were a blend of both accuracy and bias. In addition, both accurately perceived and biased perceptions of targets’ responsiveness predicted perceivers’ personal well-being (i.e., affect, coping, self-efficacy) and interpersonal well-being (i.e., more positive sentiments toward targets) immediately after the support interaction, 2 weeks later, and 6 months later. Results suggest that accurate and biased cognition during interpersonal interactions can have important consequences for perceivers’ personal and interpersonal well-being through effects on perceived partner responsiveness.