Background <p>Relatively little research has examined the associations between childhood experiences and subsequent adult self-rated health in diverse countries and cultures around the world using nationally representative data.</p> Methods <p>The current study addresses this limitation by analyzing data from the Global Flourishing Study (GFS), an international survey of 202,898 individuals from 22 countries collected in 2022–2023. Associations between a measure of self-rated physical health and a variety of childhood experiences and characteristics including parent–child relations, parent marital status, income, abuse, feeling like an outsider, health, immigration, religious service attendance, year of birth, and gender were examined using a random effects meta-analysis.</p> Results <p>Findings from the pooled analysis of the 22 countries combined in the meta-analysis showed that all childhood variables except parental marital status and immigration were associated with self-rated physical health in adulthood. Results varied across individual countries, but each childhood characteristic, including marital status and immigration, was associated with adult self-rated physical health in at least one country. E-values showed that many of these relationships were fairly robust against confounding from unmeasured covariates.</p> Conclusions <p>Findings suggest that childhood experiences and characteristics are associated with adult self-rated physical health in countries around the world. They also demonstrate considerable variation in these associations across nations and cultures, inviting further exploration and examination.</p>