The current study examined whether relationships also influence personality trait development during middle and older adulthood, focusing on the individual's perception of support from the relationship partner. Using data from the Health and Retirement Study (n = 20,422; mean age = 65.9 years), we examined the longitudinal relationships between Big Five personality trait levels and perceived support from children, family, friends, and spouses. Results found that participants who reported more positive social support and lower negative support also tended to score higher on conscientiousness, extraversion, agreeableness, and openness to experience, but lower on neuroticism. Moreover, changes in positive support across relationship partners coincided with trait changes over time, in the form of more positive support was associated with seemingly adaptive changes on the Big Five. Findings are discussed with respect to identifying social influences on personality development in adulthood.