The purpose of this study was to investigate the effect of a volunteer activity on the perceived well-being of long-term-care (LTC) residents. Residents from five LTC facilities were randomly assigned into either a mentoring or a usual-care control group. Residents in the mentoring group tutored conversational skills to English-as-a-second-language students on a one-on-one basis for 1 hour twice per week for 12 weeks. Well-being, as a global outcome construct, was measured at baseline, after intervention, and at 3-month follow-up using the Geriatric Depression Scale, Life Satisfaction Index–A, and a self-rated health question. After intervention, residents who participated in the mentoring group rated their level of well-being higher (p = .047) than those in the usual-care group on the basis of a multivariate nonparametric global statistical test. The positive effect of mentoring on well-being relative to the control was sustained at 3-month follow-up assessment (p = .029). Findings provide preliminary support for engaging LTC residents in volunteer mentoring activities to improve their well-being.