Unintended birth and mental health are major public health problems in the United States. To date, little research has examined the relationship between depressive symptoms and unintended births, and no research has examined this relationship among men. Data from the National Longitudinal Survey of Adolescent Health (N = 14,271) were used to examine the relationship between depressive symptoms among females and males in adolescence and unintended first birth in emerging adulthood. Respondents who reported higher levels of depressive symptoms in adolescence were more likely to report an unintended birth (OR 1.93, p < 0.001) compared with respondents who did not have children. They were also more likely to report an unintended birth compared with respondents who had an intended birth (OR 1.28, p < 0.05). The relationship between adolescent depressive symptoms and unintended birth remained significant, controlling for background variables, and it did not differ by gender. Adolescent depressive symptoms are associated with unintended birth in emerging adulthood. Thus, policies designed to treat depressive symptoms in adolescence may be effective in reducing unintended pregnancy among young adults.