While previous studies have shown intergenerational transmission of birth weight from mother to child, whether the continuity persists across 3 generations has rarely been assessed. We used the Aberdeen Maternity and Neonatal Databank (United Kingdom) to examine the intergenerational correlations of birth weight, birth weight adjusted for gestational age and sex, and small- and large-for-gestational-age births across 3 generations among 1,457 grandmother-mother-child triads. All participants were born between 1950 and 2015. The intergenerational transmission was examined with linear regression analyses. We found that grandmaternal birth weight was associated with grandchild birth weight, independently of prenatal and sociodemographic covariates and maternal birth weight (B = 0.12 standard deviation units, 95% confidence interval: 0.07, 0.18). Similar intergenerational continuity was found for birth weight adjusted for sex and gestational age as well as for small-for-gestational-age births. In conclusion, birth weight and fetal growth showed intergenerational continuity across 3 generations. This supports the hypothesis that the developmental origins of birth weight and hence later health and disease are already present in earlier generations.