Although previous work has examined how individual differences in attachment security affect support processes for negative events, little work has looked at how attachment security affects support for positive events (capitalization). In a 10-day diary study of romantic couples, we examined the association between individual differences in attachment security and perceptions of capitalization support. We also examined how attachment security moderated the relationship between capitalization support and daily emotions, relationship satisfaction, and life satisfaction. The results showed that stronger avoidance orientations were associated with reduced perceptions of partner responsiveness. Anxiety moderated the association between responsive support and daily outcomes; for those high (versus low) on anxiety, daily relationship and life satisfaction were more strongly tied to partners' capitalization responses, and more negative emotions were experienced regarding those responses. Overall, insecure attachment was associated with mixed reactions to receiving responsive capitalization support.