Immigrant women are less likely than their native-born counterparts to give birth to a low birthweight infant in the United States, and length of U.S. residence shrinks nativity differences in rates of low birthweight. Yet, we know little about how the U.S. context compares to immigrant low birthweight patterns in other countries. Using nationally representative data, we examine variations in the association between nativity and low birthweight in Australia, the United Kingdom, and the United States-three economically developed countries with long immigrant traditions, but different admission regimes. This study uses birth cohort data from these three destination countries to compare low birthweight between immigrant and native-born residents and then investigates how immigrant low birthweight varies by country of origin and duration in the host country. We find no significant difference in low birthweight between immigrants and native Australians, but for the United Kingdom, we find patterns of low birthweight by duration consistent with those found in the United States. Specifically, foreign-born status protects against low birthweight, though not uniformly across racial groups, except for new arrivals. The results suggest that low birthweight among immigrants is a product of several country-specific factors, including rates of low birthweight in sending countries, access to health services in host countries, and immigrant admission policies that advantage skilled migrants.