We examined the importance of social support in promoting thriving health among indigenous Canadians, a disadvantaged population. We categorized the self-reported health status of 31625 adult indigenous Canadians as thriving (excellent, very good) or nonthriving (good, fair, poor). We measured social support with indices of positive interaction, emotional support, tangible support, and affection and intimacy. We used multivariable logistic regression analyses to estimate odds of reporting thriving health, using social support as the key independent variable, and we controlled for educational attainment and labor force status. Compared with women reporting low levels of social support, those reporting high levels of positive interaction (odds ratio [OR]=1.4; 95% confidence interval [CI]=1.2, 1.6), emotional support (OR=2.1; 95% CI=1.8, 2.4), and tangible support (OR=1.4; 95% CI=1.2, 1.5) were significantly more likely to report thriving health. Among men, only emotional support was significantly related to thriving health (OR=1.7; 95% CI=1.5, 1.9). Thriving health status was also significantly mediated by age, aboriginal status (First Nations, Métis, or Inuit), educational attainment, and labor force status. Social support is a strong determinant of thriving health, particularly among women. Research that emphasizes thriving represents a positive and necessary turn in the indigenous health discourse.