We examined organizational characteristics as predictors of volunteering in two age-friendly supportive service initiatives—Villages and Naturally Occurring Retirement Community (NORC) Supportive Service Programs. NORC programs and Villages are similar in their aim to promote aging in place, as well as in their emphasis on engaging older adults as both recipients of support and contributors to the initiatives. Guided by a conceptual framework on barriers and facilitators to volunteering, our analysis considered both organizational "nature" factors, which are relatively stable over time and difficult to change (e.g., budget size), as well as organizational "nurture" factors, which are more open to managerial influence (e.g., staff receptivity to volunteers). Based on data from a 2012 national organizational survey, results indicated that organizational characteristics in terms of resources and capacity, as well as value placed on volunteers, were associated with volunteering in Villages and NORC programs. The pattern of predictors, however, differed for volunteers who were also older adult participants in comparison with members. For example, we found that having a larger staff was associated with lower levels of volunteer involvement among older adult participants but was not associated with volunteerism among members. Implications for theory and research are discussed, with an emphasis on understanding how correlates of volunteering are conditioned on volunteers’ broader roles within organizations.