Although previous studies have explored racial/ethnic differences in incident atopic dermatitis (AD) in childhood, few studies have examined risk factors associated with AD persistence. As such, we sought to examine differences in incidence and persistence of childhood AD by race/ethnicity accounting for sociodemographic characteristics and perinatal vitamin D levels. Using data from Project Viva, a prospective prebirth cohort in eastern Massachusetts, we studied 1,437 mother-child pairs with known AD status to examine the associations of race/ethnicity with maternally reported child AD. We used multivariable logistic regression, adjusting for sociodemographic factors and maternal plasma vitamin D, to estimate adjusted odds ratios (aORs) of AD incidence at early childhood and persistence at mid-childhood. Compared to non-Hispanic whites, non-Hispanic blacks (aOR = 2.71, 95% confidence interval = 1.75–4.19) and other non-Hispanics (aOR = 1.80, 95% confidence interval = 1.16–2.80) were more likely to have incident AD. Non-Hispanic blacks (aOR = 6.26, 95% confidence interval = 2.32–16.88) and Hispanics (aOR = 6.42, 95% CI = 1.93–21.41) with early childhood AD were more likely to have persistent AD. In conclusion, compared with non-Hispanic whites, AD incidence and persistence are higher among certain nonwhite racial/ethnic subgroups. Further research is warranted to identify environmental, socioeconomic, and genetic factors that may be responsible for the observed differences.