Little is known regarding how well psychosocial resources that promote well-being continue to correlate with affect into very late life. We examined social resource correlates of levels and time-to-death related changes in affect balance (an index of affective positivity) over 19 years among 1,297 by now deceased participants (aged 69 to 103 at first assessment, M = 80 years; 36% women) from the Australian Longitudinal Study of Aging. A steeper decline in affect balance was evident over a time-to-death metric compared with chronological age. Separating time-varying social resource predictors into between- and within-person components revealed several associations with level of affect balance, controlling for age at death, gender, functional disability, and global cognition. Between-person associations revealed that individuals who were more satisfied with family, and more socially active, expressed greater positivity compared with those who were less satisfied, and less socially active. Within-person associations indicated that participants reported higher positivity on occasions when they were more socially active. In addition, lower affect balance was associated with more frequent contact with children. Our results suggest that social engagement and satisfying relationships confer benefits for affective well-being that are retained into late life. However, our findings do not provide evidence to indicate that social resources protect against terminal decline in well-being.