The heritability of self-esteem was investigated in a sample of 289 monozygotic (MZ) and 452 dizygotic (DZ) twin pairs from the National Longitudinal Study of Adolescent Health (Add Health). Self-esteem was defined by four items from the Self-Esteem Scale (Rosenberg, 1965). Age of the sample ranged from 10-20 years at baseline; follow-up data were collected at baseline and approximately 1.5 and 7 years later. Self-esteem measured during adolescence at 14.9 years average age and 16.5 years average age was more heritable (42.5% and 45%, respectively) than self-esteem in young adulthood, 21.8 years average age (13%). However, the common component of self-esteem that is stable across all three time points was much more heritable (75%) than that for any single time point examined separately. The implications for genetic and environmental influences on self-esteem development are discussed.