Objective: To examine the relationships among family, friendship networks and supports, health-promoting behaviors, and healthy aging. Method: A sample of 469 Thai elderly persons was recruited using multistage random sampling. A structural equation model based on Berkman’s conceptual model was performed. Results: Family networks did not directly influence health-promoting behaviors but rather had an indirect effect through family support. Friendship networks had both a significant direct effect on the elderly health-promoting behaviors and an indirect effect via friendship support. Interestingly, friendships had both direct and indirect influences on family support to the elderly. Health-promoting behaviors had a powerful influence on healthy aging and play a significant role in mediating the relationship between family and friendship supports and healthy aging. Discussion: Findings demonstrate the importance of family and friendship roles on health-promoting behaviors and healthy aging. Intervention programs should be designed to include a collaborative approach involving family members and friends.