OBJECTIVES: Across adulthood close social partners are increasingly prioritized and socioemotional skills typically improve. We investigate whether age-related benefits in emotional well-being and social resources emerge in both cognitively normal (CN) older adults and older adults with mild cognitive impairment (MCI), and whether associations between well-being and social resources vary between these older groups and young adults. METHOD: Young adults (aged 21-34, RESULTS: Older adults with MCI had higher well-being than young adults, but lower well-being than CN older adults. Young adults generally had higher social engagement than both older adult groups and lower social quality than CN older adults. Social engagement and quality were both positively associated with well-being, especially among CN older adults. CONCLUSION: Findings suggest older adults with MCI somewhat maintain age-related advantages in emotional well-being, but not social functioning. Older adults with MCI (and young adults) may also not be as effective in leveraging social resources to support their well-being.