Objective: The purpose of this study was to examine the associations of ADHD and ODD symptoms in adolescence with occupational outcomes and incomes in adulthood within the Northern Finland Birth Cohort 1986 (NFBC1986). Method: ADHD symptoms were evaluated at ages 15 to 16 years using the Strengths and Weaknesses of ADHD symptoms and Normal Behaviors (SWAN) scale. ODD symptoms were assessed using a 7-point scale, like the SWAN assessment. Results: Symptoms of ADHD and ADHD + ODD were associated with elevated rates of unemployment, increased sick days, and lower annual incomes compared to controls for both sexes. Symptoms of ODD were associated with higher unemployment and more sick days for males, although these associations did not reach statistical significance in their association with annual incomes. Conclusion: Symptoms of ADHD were associated with adverse occupational outcomes and lower incomes. Furthermore, symptoms of ODD were associated with occupational outcomes but not with incomes.