While disparities in depressive symptoms by race/ethnicity and gender have been documented, left unclear is how such status characteristics intersect to influence mental health, particularly across early life and among a diverse set of population subgroups. This study investigates how intra- and inter-individual trends in depressive symptoms unfold across a 30-year span (ages 12-42) and are structured by the intersection of race/ethnicity and gender among White, Black, Hispanic, and Asian American young adults (N = 18,566). Analyses use data from the National Longitudinal Study of Adolescent to Adult Health, a nationally representative study of adolescents who have been followed through their fourth decade of life. We draw on Waves I-IV and a representative subsample of the brand new Wave V data. Growth curve models indicated depressive symptoms decreased across adolescence and young adulthood before increasing in the early 30s. Racial/ethnic minorities reported more depressive symptoms than Whites. Women reported more depressive symptoms than men and experienced especially steep increases in their late 30s. Racial/ethnic-gender disparities remained stable with age, except for Hispanic-White disparities among women and Asian American-White disparities among men, which narrowed with age. Overall, findings demonstrate dynamic inequalities across a longer period of the life span than was previously known, as well as heterogeneity in trajectories of poor mental health within and between racial/ethnic-gender groups. Results also suggest that Black and Asian American women experience the highest mental health risks and that interventions for reducing disparities in depressive symptoms should focus on adults in their late 20s/early 30s, particularly women of color.