Objectives: The study used data from the Canadian Longitudinal Study on Aging to investigate the relationships among social support (measured as affectionate support, emotional/informational support, positive social interaction, tangible support), social participation and depression in caregivers and non-caregivers. Method: Hierarchical multiple regression was used to investigate relationships among social support, social participation, and depression. Analyses of variance were used to examine differences in the means of social support, social participation, and depression between the two participant groups. Results: Higher levels of affectionate support, positive social interaction, and social participation were associated with lower depression scores. Social participation was a significant mediator of the relationship between caregiver status and depression. Caregivers reported significantly higher levels of affectionate support, emotional/informational support, positive social interaction, and social participation than non-caregivers. There were no between-group difference in depression scores. Discussion: The study provides support for the beneficial role of social participation in preserving caregiver mental health. Results are discussed in the context of policy and practice implications for caregivers in Canada.