<p>Income-health gradients vary in societies with diverse cultures and healthcare access levels, and generalized trust in unknown resources of health services may play a crucial role in these gradients. Multilevel models using a sample of 152,501 respondents from 89 societies are conducted to investigate the mediation effect of generalized trust in the correlation between relative income and self-rated health globally, and the moderating role of healthcare access in the association between relative income and self-rated health. Results show that individuals’ relative income significantly and positively predicts their generalized trust, which in turn significantly and positively predicts their self-rated health. In countries and regions with higher levels of healthcare access and quality, a higher level of relative income is positively correlated with increased self-rated health. This study theoretically contributes to the literature on income-health relationships by capturing medical resource access and individual characteristics. Specific policy recommendations include fostering generalized trust, improving healthcare education, and expanding telemedicine.</p>