Adolescents' romantic relationships have been associated with higher levels of depression, although their links with externalizing behavioral problems remain unclear. The present study examined the impact of adolescent romantic relationships on depression and externalizing behaviors in a large sample of 10,509 Chinese secondary school students (ages 12-19, 54.5% female). The results showed that romantic involvement in adolescence, especially in early adolescence, was associated with more depressive symptoms and behavior problems. Breakups in romantic relationships were an important factor in producing the negative emotional and behavioral consequences. Romantically involved girls experienced higher levels of depressive symptoms, while romantically involved boys had higher levels of externalizing behaviors, compared to their non-dating peers. The results also indicated that the adverse impact was stronger for those involved in romantic relationships at younger ages.