A large body of research on the "Healthy Immigrant Effect" (or "Paradox") has reported an immigrant mortality advantage. However, other studies do not find such significant effects, and some even present contradictory evidence. This article is the first systematic meta-analysis that investigates the immigration-mortality relationship from a global perspective, examining 1,933 all-cause and cardiovascular mortality risk estimates from 103 publications. Our comprehensive analysis allows us to assess interactions between origin and destination regions and to reexamine, on a global scale, some of the most notable explanations for the immigrant mortality advantage, including suggestions that this paradox may be primarily the result of selection effects. We find evidence for the existence of a mild immigrant mortality advantage for working-age individuals. However, the relationship holds only for immigrants who moved between certain world regions, particularly those who immigrated from Northern Africa, Asia, and Southern Europe to richer countries. The results highlight the need in the broader migration literature for an increased focus on selection effects and on outcomes for people who chose not to migrate or who were denied entry into their planned destination country.